Spinrite is not Data Recovery software

By | January 5, 2017

Why Spinrite is not Data Recovery software.

I am not on a crusade against Spinrite. However every so often I get tangled up in discussions where I feel the need to explain that Spinrite is not data recovery software and that the perceived magic Spinrite performs is not magic. I often encounter fanatic resistance. It is not my intention to change the fanatic’s opinion but I hope you will think twice before using Spinrite for the purpose of data recovery.

If you’re struggling to get data of a disk that’s ill behaving due to bad sectors, instead use something like HDDSuperClone (http://www.sdcomputingservice.com/hddsuperclone). It is safer (read-only) and more effective due to lower level hardware access.

Using Spinrite for the purpose of data recovery is bad practice. What it actually can do can be done faster and safer using other, sometimes free, software.

I am mainly interested in the data recovery portion of Spinrite. All over the web you will find people who unfortunately suggest to run Spinrite for the purpose of recovery of data from ‘dead’ disks. I decided to do this post after having a yet another discussion here: http://www.fact-reviews.com/info/Spinrite.aspx.

Firstly it is important to stress that Spinrite is not file recovery software. If you need to undelete or recover files from a corrupt file system, a formatted or deleted partition you’ll be wasting your time using Spinrite. In that case you need file recovery software.

Update Jan 2020: If you want more Spinrite debunking, or maybe if you think I am full of shit, I recommend you do some more reading:

http://www.hddoracle.com/viewtopic.php?f=181&t=2929 – Excellent debunking of claims made by Spinrite done by Franc Zabkar. Highly recommended!

More cautionary tales on Spinrite in Luke’s forum: http://forums.recoveryforce.com/viewtopic.php?t=114. Now I have seen plenty of people claiming that of course data recovery professionals will try put Spinrite in a bad light because it’s in their interest that people bring drives to their companies. I’d like to argue that it is those professionals that actually know what they’re talking about.

Not enough? Strong indications that the ‘repaired’ data written back to the drive by Spinrite and similar tools are just bogus, https://forum.hddguru.com/viewtopic.php?f=1&t=28780 and https://forums.tomshardware.com/threads/spinrite-hdd-regenerator-silent-data-corruption.1851619/.

To summarise the thread in a nutshell, forum member “Nesa” demonstrated that HDD Regenerator replaced the contents of an unreadable sector in the user area with a sector from the drive’s own firmware. “Lcoughey” then showed that SpinRite replaced the contents of a bad sector with random data. Worse still, SpinRite did not even alert the user that the original sector was bad, or that it had been “repaired”.

What the heck is Spinrite and what does it do?

If you understand how disk error management works, Spinrite’s miracles are easily explained by sector reallocation. Nothing Magical about that.

It is hard to get a quick and easy written description from the Gibson Research website what Spinrite actually is and does. On the main Spinrite page you will see a video that supposedly explains what Spinrite does, and also  an URL to testimonials. In essence you could describe Spinrite, it’s use, and methodology in a few sentences.

Two minutes into the video and I still don’t know what it does (yeah, ‘magic’). The ‘word of mouth’ link to testimonials does not explain at any point what it is that Spinrite does. What it does remind me of is one of those ‘get rich in 3 easy steps’ type websites. Where they continue feeding you testimonials and drag you in bit by bit. Promise by promise. Miracle by miracle. Keep claims vague so you can easily claim success or dismiss criticism.

The hocus-pocus works for a lot of people: “SpinRite gets as close to the physical media as it is possible to get – the level of raw device access”. – user comment, obviously clueless, INT13h is what Spinrite uses to read/write.

At the main Spinrite page (https://www.grc.com/sr/spinrite.htm) nowhere can I find the beginning of a description what it is that Spinrite does. Or what kind of problems I can use it for. The page header simply says ‘Spinrite, it works’. Nowhere is a list of issues or problems that you can supposedly fix using Spinrite. Also, there is no user guide for Spinrite 6 (ten years after release!).

The testimonials page lists lots of rather vague and diffuse problems that were ‘fixed’ after running Spinrite. Many of the fixes can be explained by ‘sector reallocation’ which I will explain later. Just the mere fact of software reading from and writing to a sector triggers this behavior in hard disks to replace defective sectors by spares. The vague, magic and miracle fixes are however attributed to Spinrite.

Data loss is not actually … data loss

Most testimonials do not mainly describe data loss, instead they describe some vague issue that is attributed to hard disk related problems by the user.

Because it is based on solid science and proven engineering, SpinRite routinely performs miracles of data recovery for 1/100th the cost of independent third-party data recovery services. You just run it and SpinRite fixes everything that’s wrong. Sometimes it will warn of more serious impending trouble. – GRC Website

Common reasoning among Spinrite believers appears to be: Disk is magically fixed from a rather vague, ill defined problem: Spinrite did it. Or, disk is not magically fixed: If Spinrite can’t fix it, nothing can. The latter is simply not true, however, the disk is simply given up on.

Yes, drives have error correcting built in – but Spinrite is much more thorough then any drives built in error correcting diagnostics. It’s not necessarily because Steve Gibson is a genius (although I do think he is brilliant) and hard drive makers are stupid (sometimes I wonder) it’s just that people wouldn’t tolerate the speed delays that the intensive algorithm’s that Spinrite uses in the day to day usage of their drives – user comment.

By keeping the claims vague, it easy to attribute any desired outcome to Spinrite. This is just a modest quote from the Spinrite 5 pages:

SpinRite is the most capable, thorough, and reliable utility that has ever been created for the long term maintenance, recovery, and repair of mass storage systems. – GRC website

In my own words and simply put: Spinrite is a DOS utility for hard disk maintenance and ‘data recovery’. The data recovery portion is basically nothing more than a read/write disk surface scanner: Sectors are read from and written to.

Spinrite surface scan

What can Spinrite do to recover data

What happens inside a bad disk?

It has been documented that Spinrite ‘uses’ INT13h software interrupts to read from and write to hard disks. INT13h software interrupts are an API offered by the system BIOS to access individual sectors on a hard disk. To talk to the disk on an even lower level you’d need to issue ATA commands to the disk directly. For SMART data Spinrite uses ATA commands. Reading the disk using INT13h commands and getting SMART Data through ATA isn’t anything magical. And yet, Spinrite believers will make ridiculous claims that nothing can talk to a hard disk at the low level that Spinrite does.

 …. WHY SPINRITE is better than any hard drive tool out there. Its written in ASSEMBLY because he couldn’t otherwise use his knowledge of hard drive controllers. … – user comment.

Even when ‘talking’ to a hard disk on low level, there is a lot of things you can not influence. For example, a disk’s internal software (the firmware) is equipped to deal with lot’s of different situations it might run into. Such as errors. If a disk runs into a sector it can not initially read it will employ a number of error recovery techniques to try to get the data from the sector. All that the software that requests the data can do is wait until the disk is done.

The disk then either delivers the data, or it reports and error. Up on error the requesting software can issue a new read command to force the disk to retry the whole procedure.

Bad, bad sector!

A sector that can not be read from is commonly referred to as a bad sector. Sometimes re-reading the sector multiple times results in a successful read. In some cases the disk may reallocate this sector immediately: The contents of the sector are stored in a spare sector, and the bad sector is taken out of service. The disk itself keeps track of these sectors.

If a sector can not be read at all, the sector will only be reallocated once the sector is written to. By using software, mostly specialized hard disk diagnostic and repair software, the sector is written to, signaling to the disk that it is okay to reallocate the sector and give up on the original sector data. And essentially, this is what Spinrite does when it repairs hard disks. And it accounts for many of the supposedly ‘magical’ disk repairs.

If you understand how disk error management works, Spinrite’s miracles are easily explained by sector reallocation. Nothing Magical about that.

Spinrite Data Recovery (Dynastat) and why it is a bad idea.

If a hard disk can not read a sector, basically all that the requesting software including Spinrite can do, is try to read the sector again. And it is exactly what Spinrite does when it switches to it’s data recovery mode: Dynastat mode. Spinrite will attempt to read the sector upto 1000 times (2000 even according to Wikepedia)! It will compare the successful reads and try to determine the correct, original data.

Spinrite is not data recovery software

Dynastat status window. It looks so cool!

Why this is a bad idea when we need to recover data from the disk: Often the disks that start showing bad sectors show multiple bad sectors. Sometimes ‘grouped’ and sometimes multiple groups of them. Often these disks will start showing alarming SMART data. The occurrence of multiple bad sectors is a good indication that there may be a more structural underlying cause for those sectors to go bad.

On a disk that is going bad, you do not want to force the disk to do thousands of reads on bad sectors. So, you do not want it to do what Spinrite does. The stress from the re-reads may very well be the last push the disk needs.

Also, based on this article, re-reading sectors over and over, and doing long reads over and over, does not result in reliable data at all. It produces random bytes. There is zero point to it. 2000 times zero, is still zero.

Better alternatives to get data from a bad disk.

We need to get as much data, as quickly as we can from a possibly dying disk. Why waste time (you don’t know how much time you still have) on hard to read sectors rather than getting the easy to read sectors first?

And, why not, rather than ‘fixing’ data on a possibly dying disk, a disk that can never be actually be physically repaired, copy all data we can get to another disk?

This is why all people that are serious about data recovery, including data recovery labs will try to clone a hard disk first. They will employ software, or a combination of specialized hardware and software that first gets the easy to read data. This is often the bulk of the data. Areas that are hard to read will be processed last. If needed such combinations of specialized hardware/software can even avoid using a specific disk head or avoid using corrupt firmware.

For the hard to read areas re-reads can be tried. Also the bad areas can be approached from different angles: reverse cloning.

Specialized hardware is expensive. If data is not valuable enough to sent the bad disk to a data recovery lab, the end user can use specialized cloning software. In essence this software ignores read errors. Also, as bad sectors sometimes tend to group, the software typically skips a number of sectors after a read error. This to avoid bad sectors and lengthy error recovery procedures from the hard disk itself. After the software gets all the easy to read sectors, it can turn it’s attention to the sectors it initially skipped.

Examples of such software are Ddrescue (free) and my own tool DiskPatch (commercial).

There is only one bad sector anyway. Can I fix that?

Under circumstances it is actually safe to ‘fix’ a few bad sectors. I know I am on thin ice here, but I had a few of those disks myself which turned out to be okay: For example, I had a RAID controller flagging a array member as ‘bad’. I took the disk from the array and examined it’s SMART data. The disk looked healthy apart from two sectors pending reallocation.

Such sectors could not be read but since no data could be recovered from them they are pending reallocation until data is written to them. In such a case you can run a DiskPatch read/write surface scan after which the sectors will be reallocated. You can use Spinrite for that purpose as well. Run some more surface scans to make sure the disk is stable. Monitor the disk closely over the next few weeks (SMART). To do this automatically you can install a SMART monitor.

https://www.grc.com/sr/spinrite.htm (Spinrite)
http://www.diydatarecovery.nl (DiskPatch)
https://www.gnu.org/software/ddrescue/ (Ddrescue)
http://www.linuxjournal.com/article/7684 – Comment section is hillarious

46 thoughts on “Spinrite is not Data Recovery software

  1. George Steele

    I think you are being too skeptical in your description. Yes, when a drive discovers that the ECC algorithm has been triggered in order to reconstruct data from a sector that has errors, it can automatically recover the data and relocate it. But it will not do so for error run lengths below the preset that triggers relocation. What Gibson is saying, correctly, is that only a surface scan – one that looks at all the sectors on the disk, done periodically, will catch failing sectors as they pass that preset, but before the ECC is no longer capable of reconstructing the original bit pattern. He is also correct that servos are imperfect, and that heads don’t always track perfectly. When an error area of the disk surface “grows” into a sector from, say, the right, by seeking left and then returning, the head will pass over the sector slightly skewed from its original trajectory – which may allow a signal improvement sufficient to allow the ECC to pick up bits formerly missed, recover the data, and then relocate it. That “wiggle” reading is one of the things Spinrite does, which may – in desperation – allow recovery of data. As for Dynastat, there’s no interaction between a head and the disk surface during a read – the read process is passive. So multiple passes over the same area won’t worsen a media surface unless the flaw is sufficient to displace the media coating and impact the head. If that’s the case, the drive would have crashed the first time you tried to read it. There are issues with respect to when you use Spinrite, relative to the nature of the problem you are encountering, but if you think a drive is at its “about to die” point and you have data not yet saved, the best approach is to save what you can, then Spinrite it, and try to get the rest. When Dynastat does its rewrite, of course, it does interact with a defect area. But if it does a multiple overwrite, the magnetic remanence and strength of the signal can increase sufficiently to return the sector to a readable condition. At that point, copy the data, and toss the drive is the appropriate action.

    1. Franc Zabkar

      “Wiggling” makes no sense for an embedded servo. It only has value in stepper motor drives which are subject to gear lash and thermal expansion. An embedded servo will ALWAYS position the headstack directly on-track, irrespective of the direction and speed at which it approaches the target. That’s because, unlike a stepper motor, a servo incorporates positional feedback.

      In fact the drive’s own internal error recovery algorithms include “wiggling” to account for off-track writes during external shock events. For example, the error recovery procedure in a Conner Peripherals 1GB drive includes +/-8% servo offsets. That is, the headstack is deliberately positioned to either side of the track by a distance corresponding to 8% of the track width. SpinRite has no control over this behaviour, or any other error recovery aspects of the firmware.

  2. Joep Post author

    Hi George,

    Thanks for your comment!

    The most important point I am trying to make is that it’s a bad idea to use Spinrite for data recovery. Any reputable data recovery lab and technician will confirm this. Key is to do as little as possible to an ill behaving disk, and get the data off as quickly as possible. Spinrite does non of that, instead it ‘recovers’ data on the disk itself, and to do so it intensively reads the disk. It doesn’t matter if they’re reads or writes.

    The mechanisms you describe to recover data from hard to read sectors are already done by the disk itself (the wiggling and all) using error recovery procedures. There is zero added value in using Spinrite, only added risk. So, bad idea.

    The data ‘recovered’ by Spinrite using dynastat is unreliable data: there is no way of telling the data is actually correct. For critical data one could say that recovering no data at all is better than recovering potentially corrupt and unreliable data.

    For the disk repair part, it’s lots of smoke and mirrors and technical mumbo-jumbo to describe a read/write surface scan to trigger sector reallocation.

  3. Thomas Adkins

    I comment your calling BS on the nebulous language used both in advertising and in so-called testimonials. Firstly, there is a huge emotional component in losing precious data. This leads, for better or worse, to an emotional response to a perceived success. That emotion has to be attributed to something, why not the software being used? That seems logical to the user.

    But beyond this is a desire to understand the workings of these every-day devices, computers. Even technicians can get suckered this way, because a person could conceivably have an A+ certificate and years of experience as a technician, yet still not have a grasp of the workings of magnetic media storage. The problems of computer workings therefore tend to go much farther into scary territory than other, more easily-imagined problems, like burglary or car accidents. There are nagging, unanswered questions.

    The marketing for SpinRite is a custom fit for these psychological issues. The language used is rife with nebulous benefits, inviting the unwary to see the product fits their need. Then, if the product seems to work, there might even be another testimonial inviting others to join the blue waters. But facts are facts!

    There are very good reasons that there are no detailed illustrations of how the product actually works, reasons that go way beyond proprietary or trade secrets. Giving details brings a person out of la-la land. Giving specifics encourages discernment; and allows the buyer to better apply reason to their purchase. Thanks for such a well-balanced article.

  4. Taz

    (meh) You’re correct about Spinrite in that it really isn’t recovery software. That said, it’s still a useful tool for that purpose if you are in a hurry and willing to take the risk of performing recovery on a failing disk. Spinrite is the only easy method I know of to tap into the very sophisticated self maintaining firmware now present on all disk drives. It’s good for beating disks to do their job.

    My problem with Spinrite is that it is limited by the drive manufacturer. Who has a vested interest in making sure his disk never reallocates and permits warranty return. This is what leaves people with marginal disks…Failure to reallocate.

    Have come to accept this situation. All disk manufacturers cheat. So my real interest is finding an easy to use tool which will mark blocks as bad (allocated) within the filesystem. Say any block not capable of reliably delivering it’s content within some user selected time threshold. Sadly, no one really offers such software.

    SMART is so useless as to be a joke. Any potential for that ancient IBM system was lost when disk manufacturers gamed their failure thresholds. SMART = Big waste of time.

    1. Joep Post author

      If you’re in a hurry use Spinrite? it’s slow as … Anyway, if you are in a hurry to get data from a failing disk then clone it. Do not potentially beat it to death using Spinrite.

      Spinrite does not tap into any firmware. It uses simple extended BIOS int13h interrupts to read and write sectors.

      Hard disks do not fail to reallocate, they only do it in specific situations and for good reason I think. A disk will reallocate if 1. it can get the data from the sector or 2. if user gives up on data by writing to sector. So it reallocates only on specific conditions and as far as I am concerned there is good logic behind this.

      IMO flagging clusters at the file system level is a bad idea, but if you really want to no additional software is needed as it is what file system checkers like chkdsk do.

    2. Franc Zabkar

      Mine is not to reason why, but you can mark a particular sector as bad using hdparm under Linux:

      hdparm –make-bad-sector nnnnn /dev/sdX

      I believe it uses the ATA Write Uncorrectable command to create a pseudo-uncorrectable sector. I expect that a subsequent CHKDSK (or ntfsfsck) should then add this sector to the $BADCLUS metafile.

      1. Joep Post author

        Interesting! It shouldn’t be too hard to write some code that edits the FAT to mark a cluster bad or edit $BADCLUS on NTFS but having the drive itself flag it as un-correctable is more graceful.

  5. Michael Duval

    Priceless, im not agains spinrite, but these are the reasons ?!

    SpinRite is hdd/sdd recovery software, not “user error: give me my data back” software.
    That being said, its proprietary software and by default closed source. But if you really want
    to know how it works, there are many podcasts on it. But you did not take the time to
    grep through the 600+ transcripts ?

    Having read the article, i find your technical knowledge and investigative effort lacking . There are many flaws in it.

    Spinrite is a solution for poorly written firmware by drive manufacturers (no exceptions) and
    the operational problems that arise from it. A situation where most people who use computers
    will eventually run into.

    And since there is no better alternative, i have this piece of software in my IT recovery arsenal.

    Thanks for the laugh, it was a real day brightener.

    1. Joep Post author

      Selective reading is a talent too I guess.

      – It is advertised as data recovery software.
      – It makes extraordinary claims.
      – These are backed up by pseudo-scientific mumbo jumbo.

      I have no problem with closed source. Explaining how something works does not require open source. I should not have to go through 600 transcripts to find out how it works.

      In my post I explain I understand perfectly well how it works and that it does in fact nothing of the claimed low level stuff it claims it’s doing. It does nothing to circumvent or correct poorly written firmware, and in the end it depends entirely on this firmware.

      If you have this software in your IT recovery arsenal then I sure hope you do not provide services to others.

      Claiming errors in my technical knowledge or investigative efforts is meaningless without rebuttal. Where exactly am I wrong? I am not trying to start a pissing contest, I am actually curious. If you find factual errors I’ll be happy to update my blogpost.

  6. Mike

    I like listening to Steve on SecurityNow! podcasts and since he doesn’t go after people for using borrowed copies of SpinRite, I don’t think he’s a charlatan, as you kind of hint. (Whereas you have a financial interest in dinging SR.) And although I’m an engineer, I don’t know enough about hard drives to know if what you’re saying is right. (Whereas, if I have the story right, Steve was threatened with legal action for reverse engineering hard drives. If true, gves some credence that he might know what he’s talking about.)

    Having said all that, I’ll give you an example you didn’t mention where SpinRite finished off my hard drive.

    I was having read problems, where Windows would pause with a white “Not Responding” warning. Instead of immediately cloning the drive, I thought “I’ll just SpinRite it.”

    Bad idea. Turns out that the heads were coming loose from the actuator arms. (A problem that seems to plague Hitachi drives.) When SpinRite went into DynaStat mode, the constant thrashing back & forth of the heads knocked them off their arms. Although in my case the hard drive repair lab said that the platter wasn’t damaged, it could have been.

    So I agree. I don’t use SpinRite any more to save a failing disk. I use it for periodic maintenance, to force my drives to touch every sector so that the firmware can do its thing.

    1. Joep Post author

      Hi and thanks for the comment,

      I don’t recall using the word charlatan. I do feel the info on the Spinrite website is misleading and I try to explain why, but I guess you could read it like that. I do not only claim stuff, Steve himself in sources I point to says so much that disks are accessed using BIOS interrupts. So, nothing special, my own tool DiskPatch does that too.
      Again: Spinrite is NOT data recovery software and it is dangerous to position it as such. And also, what Spinrite does is hardly anything special. Much of what it claims to do is not possible without using special hardware which is why data recovery shops use specialized tools like the PC3000. And then they only employ those tools to get an image/clone of the dying disk as quickly as possible rather than hammer it to death.

      1. Franc Zabkar

        Ironically, one of SpinRite’s own testimonials demonstrates just how absurd SpinRite’s “data recovery” methodology really is. Had the user used a proper cloning tool at the outset, ie one that knows how to deal with bad heads/media, then there would have been no need to “repair” the drive.


        From: Nathan Huebener in Marion, Iowa
        Subject: Spinrite violates the laws of physics
        Date: 25 Feb 2014 01:33:22

        My brother’s laptop was very slow when booting and while being used. The hard drive was suspected as being bad, Norton Ghost tried to clone it and failed. It was not pretty. I ran Spinrite at level 2, and then was able to clone it to another drive. It cloned over perfectly and no bits were lost. After the new drive was installed and running, I opened up the bad drive and looked inside. Inside were tiny metal shavings. From what I understand, if a piece of dust goes between the head and the platter it’s game over for the drive. Somehow, Spinrite was able to fix the drive just long enough to clone it.

        Spinrite has also fixed my Intel X-25 Extreme 64gb SSD, it was showing some sector access times over 600ms.

        Spinrite user and Security Now listener since episode 1,

        Nathan Huebener,
        Marion, Iowa

        1. Joe

          Yeah just my 5c here, I’ve run Spinrite on a failing 700gb drive ( a Seagate Barracuda ST3750330NS) That I recovered from the dreaded index overflow situation that bricks it. However it took a while before I got to cloning it, and it was handled and moved at work. At the time of the bricking it had no problems but when I tried to clone it now after, like I said, maybe some time with excessive G-forces in a moving box, the cloning was terribly slow and eventually failed.

          Being old-school I ran Spinrite, level 2, but I got the division error it gets on larger drives >500gb (Haven’t figured out if it’s possible to avoid somehow) I managed to move over some files manually after this but some caused IO errors and it did not clone correctly when I tried. So I ran Hard Disk Sentinel’s Surface scan.

          The surface was light green, readable and fast up until the 500gb point where Spinrite cut out. So apparently it’s not snake oil. Or it is a big coincidence that it just happened to be the very last 200gb of the drive that failed.

          I wish I could get over the 500gb limit somehow and run SR over the whole disk to be able to see what happens.

          On a second note, what cloning software do you recommend that is ruboust and knows how to handle unreadable sectors?

          1. Joep Post author

            It’s typical this type anecdotal, ignorant testimonials that keep the myth alive.

            Spinrite does not have a problem with disks > 500 GB. So, Spinrite AND HD Sentinel both having a problem beyond that point means NOT that Spinrite ‘fixed’ that disk upto that point but that the actual problem starts at that point. They simply both ‘cut out’ at the same point.

            Best end-user cloning software to handle bad disks would be HDDSuperClone.

  7. Ike

    Thank you for this article! It convinced me more than ever I need SpinRite for my particular issue!

    1. Joep Post author

      Yeah? And what issue would that be? It just won’t die already?

    1. Joep Post author

      Assuming you mean ulterior, It is a common tactic to raise doubt about motives if you can not prove the message you do not like or do not agree with to be incorrect.

      It is obvious you doubt my motives, if you would not have, you would not have even mentioned them.

      My motivation to write the article is frustration with false information. Much of the information on the internet about Spinrite is plain wrong and it just keeps spreading. No, I do not mind if you purchase a copy of HD Sentinel to safe guard your hard drive’s health without making the ridiculous claims that are being made about Spinrite.

  8. Luke Coughey

    This was a well thought out and researched article. I don’t understand why people are so hard pressed to blindly use a program that is, without a shadow of doubt, losing data from almost every sector it “fixes” while risking a completely fatal head crash, without ever recovering a single sector from the failing drive in the first place.

    I’ll take an 80% clone of a drive that crashes before completion over a drive that was 99% fixed by SpinRite just before it completely crashes.

    1. Joep Post author

      Thanks for the feedback! Good to hear this from a professional.

  9. Luke Coughey

    I’d like to add that SpinRite 6 was released in 2004, designed to handle hard drives built in the 90’s. There have been a lot of changes to hard drives since then.

    1. Joep Post author

      Yeah but I believe even back then it’s core functionality was no more than forcing sector reallocation dressed up with lots of gimmicks and mumbo-jumbo. So yes, it ‘worked’. After running it a disk that could not be mounted (because Windows choked on bad sectors which indeed can happen) all of a sudden was mountable again. But that’s fairly simple to understand and does not require any magic. Simple sector reallocation explains that perfectly.
      More serious is that even back then if it was used for data recovery, there’s a big risk of the software pushing the disk over the edge.

  10. Dwight Moody

    Spinrite is not for people who accidentally delete stuff. It is for the recovery of failing hard drives. I have used it numerous times to recover data from disks that had failed and it worked exactly as expected 80% of the time. I’ve even seen it fix an SSD through only a pre-scan. That was pretty unexpected.


    1. Joep Post author

      If you ever struggle with a failing disk then don’t run Spinrite, period. Unless you have nothing to lose. Instead clone disk with something like HDDSuperClone (http://www.sdcomputingservice.com/hddsuperclone).

      Spinrite does nothing special to read disks (see above article). HDDSuperCLone on the other hand has much lower level hardware access to disks as Spinrite. AND it only READS the troubled disk unlike Spinrite which is it’s biggest flaw.

  11. fred

    We see you are from China:
    If you’re struggling to get data of a disk that’s ill behaving due to bad sectors, instead use something like HDDSuperClone…

  12. Peter Blaise

    Drive self-reallocation of sectors is supposedly disabled by Spinrite during data read.

    From https://www.grc. com/srrecovery.htm

    “… Disable Auto-Relocation – Hard disk drives “heal themselves” by replacing defective sectors with spares. This gives the drive the favorable appearance of being “defect free”, which is how the drive’s manufacturer wants the drive to always appear. The problem is that the drive does this on its own, without asking or notifying, and in the process vital data is too-easily lost. When a troubled sector is replaced by a spare, that troubled sector can never again be accessed. The FIRST THING SpinRite does when it starts examining and working with a drive is to completely disable the drive’s built-in automatic sector relocation. This way the drive can’t whisk the sector away the first time it’s not easily read, and SpinRite can study the sector to recover its data as much as necessary. Erroneous Data Reading – With the drive’s defective sector relocation disabled, SpinRite is now free to work as hard as it wishes to recover the sector’s data. So it begins re-reading the sector. But rather than ignoring the data from a bad read, SpinRite uses its unique “hardware level access” to read whatever data the drive was able to get from the bad sector. SpinRite begins assembling a database of this bad data, which will be used by SpinRite’s “Dynastat” data recovery system. It often happens that during this re-reading and data collecting phase, one perfect read will be received just by trying to read the sector many more times than other software ever bothers to. In this case, SpinRite reports perfect data recovery then re-enables the drive’s auto-relocation so that the defective sector is now released and replaced with a perfect (but empty) spare. The region is then tested extensively and the data is perfectly written back onto the drive …”

    – – – – – – – – – – –

    So, in your own testing of SpinRite, what did you find regarding a drive’s self-reporting of reallocated sectors before and after a SpinRite run where SpinRite claimed recovery ( “perfect” or not )?


    1. Joep Post author

      “Supposedly disabled”, you said that right. Do I believe this? No. Would it be useful if he actually could? No.

      So what happens when a disk can’t read a sector? Does it secretly hide this from us? And is this statement true: “vital data is too-easily lost”? No. A hard drive will ONLY swap for a spare on read if it was actually able to read/recover the sector. So, on READ it will never reallocate the sector if the read is unsuccessful. IOW if it does reallocate on read we know it was actually able repair the data using ECC. ECC correction is far more reliable than Spinrite Dynastat. Dynastat is close to useless which I already mention in the post.

      Now let’s ASSUME it can disable automatic reallocation (which it can’t) and that Dynastat made any sense. Would it then be wise to use Spinrite for data recovery? No. First of all it writes recovered data to the patient drive which is a ‘not done’ in data recovery. Second, it does not prioritize. What I mean is, as soon as it hits a ‘bad sector’ Dynastat will start hammering it (2000 reads and this is ever without taking into account that the drive will do re-reads itself to recover the sector). Next sector again, and the next and then the disk is dead. All sectors it never read: Lost. All sectors it did recover (let’s assume for laughs), useless as we can’t reach them since the disk is dead. Any serious data recovery imager / cloner will first work around the troubled areas (even disable entire heads), get what is easy to get first and then attempt the bad areas. From a data recovery standpoint of view Spinrite is utterly useless even IF it was able to do what it claims to be able to.

      EDIT: Didn’t notice the question at the end, sorry. It is un-testable. Exact same thing could be done with my own software DiskPatch (surface scan feature, however DiskPatch also offered a disk clone option) without all the hocus-pocus. Either you get the (ECC corrected) data > you write it back to disk > disk decides to reallocate or not, or you don’t get the data and then decide if you want to get rid of the sector (by writing to it > triggers reallocation).

      He manages to sell a feature that hard drives offer as something that was accomplished by using Spinrite.

      That he claims to write perfect data back is a claim he can only make if he relies on ECC correction. Else there is NO way he can guarantee to write ‘perfect’ data back. Read the ATA specs. He claims the impossible: If a hard disk physically does not offer access to certain features you can not bypass that with a software only solution. Data Recovery engineers use quite expensive hardware/software complexes for that (PC-3000 etc). Besides that he does not even go that deep to do reads/writes he uses ext13h BIOS software interrupts. If you want to go one level deeper, software only look into something like HDDSuperClone (http://www.sdcomputingservice.com/hddsuperclone).

  13. albytastic

    I recently bought Spinrite in order to run its maintenance program after listening to Steve for many years on Security Now.
    I bought it mainly because I have a large number of HDDs containing Terabytes of Data.
    But when I ran Spinrite on an empty 2TB disc I got the “Division Overflow Zero” warning.
    The disc was empty because it had seemed to pause and stutter in various places when running HDDTune error check (quick) on it.
    Since I knew that a full format (as opposed to a Quick Format) can sometimes re-locate faulty sectors I ran a full format overnight then ran Spinrite (which is now still running).
    It completely passed the area which had previously been a problem area and had resulted in the DVO error, although it still slowed down when dealing with this area.
    As far as I am concerned I still think Spinrite is an excellent tool but will also start running a full format on empty discs first (this also helps to delete all data on them as opposed to a quick format).
    So my suggestion is to run HDDTune on the quick error check, then if it shows a sudden stop for a few seconds consider transferring all the data to another disk and then perform a Full format and finally run Spinrite.

    1. Joep Post author

      So with that you purchased a program that hasn’t been updated for years. The “Division Overflow Zero” isn’t a warning, it is a bug which would be easily fixed if the program was properly maintained.
      Stick to the 2 TB disks because Spinrite won’t be able to run on anything larger than that.
      Yes, a full format can help ‘force’ the drive’s firmware to reallocate bad sectors, bad sectors are reallocate on write. It signals the drive “I am giving up on the data in the bad sector, reallocate it. This is the only thing Spinrite can do too with bad sectors after finishing it’s obnoxious dynastat (let’s read that thing 2000 times in a row) that has the potential of pushing any unstable disk over the edge.
      IF a disk would contain data the best option is to clone it rather than running a potentially destructive tool like Spinrite. HDDSuperClone is closer to the hardware than Spinrite, even the free version.

      “The disc was empty because it had seemed to pause and stutter in various places when running HDDTune error check (quick) on it.”
      Keep a close eye at S.M.A.R.T. values for for this disk, specially reallocated sectors and pending sectors. Wisest is probably to replace it although I have seen disks which developed a couple bad sectors, reallocated those, and ran for many years since that.
      I assume you mean HDTune btw. A nice free alternative is http://hdd.by/victoria/ (Russian website, software in English though).

  14. Jonathan

    I own a licensed copy of SpinRite6 having first used it back in the days of MFM and RLL hard disks where access to the physical drive was still ‘real ‘ – no abstraction, no LBA etc.
    Certainly in recent years I’ve felt that it’s really failing to keep up with the times – especially being based on FreeDOS and limited in general to older hardware and legacy IDE/SATA modes (presumably it’s a total non-starter on UEFI systems now).
    It’s useful to see your write-up about its “features” as I have always taken the sales pitch with a big pinch of salt, and Steve Gibson seems a somewhat eccentric character.
    However whilst I don’t really dispute anything in this article I have to say that I’ve successfully “saved” a fair few drives using SpinRite and I can’t recall it ever making one worse.
    I think a big driving factor in the past (at least for me) was that I didn’t have the luxury of a spare drive I could clone to, so despite all the bad practice and risk of doing an in-situ “repair” this tool always felt safe enough to use and pretty much always returned be to a working drive whenever I got to a situation where reads would grind to a halt at the filesystem level because of a bad sector.
    I’ve felt for a long time that it would benefit from being ported to Linux in order to increase hardware support and obviously an update to increase the supported drive sizes etc. However as we gradually all move away from spinning rust to SSDs I guess this whole approach becomes less relevant.
    All this said, after allowing DynaStat to run for hours and hours I have never yet seen the affected sector marked as being recoverable – it’s already a red ‘U’ although it’s always at least managed to kick the drive into reallocating that sector.
    Next time I have a drive failure I’ll give the other tools you’ve mentioned a spin and see if I can get a better (or perhaps just quicker) result.
    Cheers for writing this – it’s been an informative read!

    1. Franc Zabkar

      Don’t be misled by an absence of unrecoverable sectors. The following real world tests demonstrate that SpinRite actually causes insidious (ie unreported and undetectable) data corruption in some cases.

      SpinRite – A Data Recovery Program?


      SpinRite & HDD Regenerator – silent data corruption:

  15. Jason

    I have owned Spinrite for many years. I used to run it on every hard drive. It has rarely fixed anything. I have had a number of hard drives fail over the years and Spinrite usually doesn’t even recognize them if they have failed. I believe 98%+ of what Spinrite does is just the hardrive using its own built in ECC or relocation to fix failing sectors. There is some value in reading and writing every sector to refresh them. However, it takes Spinrite 6 a full two weeks to do a full maintenance run on a 2TB SATA drive. And to make it worse, the drive and entire system are offline running in DOS mode for the entire time. I don’t have any production drives that can be taken offline for 2 weeks for maintenance. Spinrite is near useless these days. Gibson seems to be spending some small amount of time working on a 6.1 version that is supposed to be much faster, but I’ve been hearing that for several years. If 6.1 comes out soon, I will give it another try, but for now, it seems to be a thing of the past.

  16. Robert Bullock

    One thing it is useful for IMHO is recovering floppy disks. I have had it fix weak sectors and allow copies. Yes the head touches the disk. But it also could be consider cleaning said surface. Followed by a floppy drive head cleaner, then a re-read attempt has worked for me.

    It’s important to understand what Spinrite does, and yes it’s not magic. But like most tools if you understand how they work, they are useful.

    I will say also my Spinrite 6 license also got me a 5 license which is a nice addition.

    1. Joep Post author

      Maybe. Of course it supports FAT so it can reclaim clusters marked bad but a format would do. I would have to look up what either BIOS or DOS interrupts would allow it to do with regards to ignoring ECC (long reads), perhaps it could do something there that for example a windows based surface scanner would not be able to do. All the supposed interaction with firmware is moot with regards to floppies of course. So, yeah, maybe. But still a far cry from all the wild claims the websit/Steve makes with regards to hand drives and SSD.

  17. RussG

    I’ve used Spinrite since it was released. I does what it claims and was originally (as mentioned above) to work with floppy drives. I’ve used it from one sided 256k floppy’s to HDD’s. It’s just another tool in the tool box and it was one of the only tools available back in 80’s. What utilities are available today that are still in use from the 80’s? It still works albeit not as well as other modern utilities. I’ll confirm that what JoeP has written is true. If anything buying the program helps support Steve Gibson whose been a White Hat forever.

  18. RussG

    Well I read it wrong and sort of retract what I said about Joep’s comments. What I do want to say is that Spinrite is a usable tool that was exceptional when it was released and still relevant today if only to support the author.

  19. Franc Zabkar

    In the following forum posts I have attempted to examine every claim made by Steve Gibson in respect of SpinRite.

    Deconstructing SpinRite:

    I concur with Joep that SpinRite is at best useless and at worst data destructive. I say this as someone who has used SpinRite during the MFM/RLL days of the late 80s and early 90s. However, after HDD manufacturers switched to voice coils, embedded servos and IDE interfaces, SpinRite instantly became irrelevant.

    1. Joep Post author

      Very thorough research there Frank, the HDD Oracle forums! As a matter of fact I will link to it in the post, people may not go through all the comments.

  20. Johnny Kuhn

    Spinrite is an absolutely useless software. Unfortunately I fell for the scam and bought a license. I believed that the promises of the money back guarantee were true. But neither does anyone at support answer to my bug report nor does the “sales team” (which probably doesn’t even exist) claim my money back guarantee. We will file a criminal complaint. So if you read this, please don’t fall for it and buy the license, because the software doesn’t do what Steve Gibson promises in first place, nor do they pay back the money if the software doesn’t work. I wish I had done a little more research before I paid those scammers the money.

    1. Joep Post author

      Well, and THAT surprises me. The support team is indeed one guy (used to be, called Greg). But from what I have observed they do follow up on support requests and they do returns/refunds. What I also noticed is they change their support email every year: so right now it probably is support2020@grc.com. Hope this helps.

  21. Jason

    The only information I have is what Steve verbally said himself in the various podcasts over the year. I’ve never been a hardware guy, and Steve is not very good at explaining the how it works in any one attempt.

    From what I’ve pieced together. The primary utility is to force the drive to read/write all of its own sectors so it can realize there’s a problem and if the problem isn’t too bad the ecc can get the data, move the data to a different sector. Also, refreshes the data by having it re-written to the drive if you choose level 4 for maintenance, which you’re not supposed to do if you’re actively having an issue.

    It’s been over a decade since I tried to used the ungodly slow software. Anyway, he himself says if you start getting those bad sectors, you really need to start thinking about replacing the drive. In one specific of the podcasts, he did talk about how the fact that if it can’t read a sector, it will try over and over. Sometime it will try reading a sector from different parts of the drive in the hope that the head coming at the sector from a different angle will help it gather enough of the bits that the error correction will carry it the rest of the way. or something to that effect. I also vaguely recall him admitting that on very bad drives, this could be the death knell for it.

    As for my personal experience with the software. I don’t use it. Not that I don’t think it could have a useful place, but with today’s drives I’m not going wait around for literal WEEKS for it to complete if there’s something wrong with it. A good backup and new drive is just faster and this is especially true if I’m going to need to replace the failing drive anyway.

    I did have it save a computer ONCE. It was as laptop with full disk encryption that wouldn’t boot and we couldn’t recover anything off of it, so I tried it over night. If it failed we were starting over anyway. SpinRite didn’t get anywhere near done, but I guess it got far enough because I cancelled the process and the laptop started up without error.

    Supposedly, he’s working on updating SpinRite again now that SQRL is finished.

  22. Jon Forrest

    Here’s my experience with SpinRite 6. It isn’t positive. However, to their credit, GRC did refund
    my money so I have no beef with them. (This is from 2010).

    Why I’m Going to Return SpinRite for a Refund

    I bought SpinRite with some trepidation. First of all, the latest
    version was first released in 2004 – more than 6 years ago. A lot has
    happened in the last 6 years. SpinRite also has a checkered reputation,
    some even calling it “snake oil”. In the early version of SpinRite this
    reputation was clearly unwarranted because SpinRite was the only product
    that could non-destructively change the interleave factor of a disk
    drive. These days most people don’t even know what an interleave factor
    is, and most (all?) drives don’t even have an interleave factor, so this
    ability is of no use anymore.

    However, I was looking for a product that can analyze my rapidly growing
    pile of disk drives that are in questionable condition. I want to know
    which drives are still usable, and which drives could be made usable.
    SpinRite is the only product I’m aware of that claims to be able to do
    this. So, knowing that SpinRite has a 30-day guarantee I decided to take
    my chances.

    In summary, I was very disappointed. SpinRite is uncontrollable and
    incomprehensible. I have no idea if it does what it claims because most
    of the time it would have taken weeks or months for SpinRite to finish
    working on a drive. Most of the time SpinRite didn’t obey the simple
    commands I gave it so it was very frustrating to work with. Even when I
    got it to do what I wanted, I was often puzzled by the various
    statistics it displayed. I was left not trusting what I saw. I’m
    planning on asking for a refund.

    What follows are the notes I made while running SpinRite on various SATA
    drives. In all cases I used a Dell Optiplex GX280 with the A08 BIOS,
    which is the latest BIOS for this system. These notes are not in order
    of importance.

    1) “Push spacebar to select another screen to view” only works rarely.
    Most of the time it doesn’t do anything. This makes it very difficult to
    monitor what SpinRite is doing.

    2) When #1 did work, using the arrow keys or number keys would sometime
    work, and sometimes make the display choice window close. There seemed
    to be no rhyme or reason for what the arrow and number keys did.

    3) The Detailed Technical Log says in the “dma channel:” area “no, fast
    PIO mode”. Why isn’t dma being used? The computer can do it when running

    4) I left SpinRite running doing level 4 check on a 500GB drive over the
    weekend. When I came in on Monday, all I saw on the screen was a window
    saying “SpinRite has completed its work with this system …”. I saw no
    sign of any problems that were detected or repaired. There should have
    been some way of seeing a status report of the work done by SpinRite.

    5) When selecting Drives and Partitions, there is sometimes a ~5 second
    delay between the time you press space and when the partition shows up
    as selected. This didn’t happen with every disk.

    6) It takes several minutes for the “Selecting Drive For Use …” window
    to go away and for the test to start. What is going on during this time?
    Again, this didn’t happen with every disk.

    7) When the “Select Screen to View …” windows comes up, it doesn’t
    always go away after a choice is made.

    9) There should be a way to tell SpinRite that I don’t care what’s on
    the disk so it make a destructive pass through the disk to find hard errors.

    10) Sometimes I’m watching the “Graphic Status Display” but then the
    display switches over to the DynaStat data recovery display without me
    doing anything.

    11) When I tried to look at the SMART System Monitor I received a
    message saying that SpinRite doesn’t have access to SMART data published
    by the current physical drive. I know this isn’t true because I just
    took the drive out of another system that was able to display SMART data
    for the drive. In fact, the drive had 189 relocated sectors, which is
    why I took it out.

    12) I’ve been stuck in the DynaStat Data Recover window for over a day
    now. I try typing the space bar to go to another window but nothing
    happens. If there were some way of knowing what’s going on I might not
    feel so bad. But, all I see are the moving rectangles in the top right,
    the “Initiating DynaStat Recovery System” blinking, and the bit counts
    changing value. The cylinder, sector, and head numbers change every so
    often, which is to be expected. However, the “data samples”, “first
    uncertain bit”, “last uncertain bit”, and “uncertain bit span” don’t
    have any numbers next to them. The “unique samples” and the “discarded
    samples” numbers show 0. None of these has changed since I started
    running the program. Nor has the straight line through the center of the
    main window. I’m about to go away for 5 days. It will be interesting to
    see what’s on the screen when I return.

    13) I’m back. I notice that the display on the bottom left of the screen
    says cylinder 13, sector 14, and head 245. I didn’t know that disks
    these days have 245 heads!

    14) I suspect that the disk I’ve been running SpinRite on for 5 days is
    unrecoverable. That’s fine, but SpinRite should have suggested this
    possibility and given me a choice of what I wanted to do next.

    15) After running for ~3 hours, the status report on the screen saver
    says the Time Elapsed is 0 hrs and 0 min.

    16) In the DynaStat Data Recovery window, there’s a section that has
    three values, data samples, unique samples, and discarded samples.
    What’s strange is the the sum of unique samples plus discarded samples
    does not equal data samples. Where did the other samples go? I’m seeing
    the total off by 2.

    17) In the DynaStat Data Recovery window, I see those waveform-like
    shapes. However, the only thing that seems to be happening is that every
    ~8 seconds the number of data samples goes up. But, the bit counters on
    each side of the screen aren’t changing and neither the first and last
    uncertain bit counters. I have no idea what’s going on.

    18) I’m running a level 2 check on a 400GB SATA drive. When I left last
    night, I was at 0% complete. Now, ~14 hours later it’s still at 0% complete.

    19) I’m looking at the Graphic Status Display window. Near the bottom
    there’s a “sector status key” section that shows the various characters
    that appear as the sectors are analyzed. However, the character I’m
    seeing is the ‘?’ character, which doesn’t appear in the sector status
    key section.


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