“Windows protected your PC”
Modern versions of Windows have a feature called SmartScreen, which warns about unknown files. This means software without a big company behind it and/or a huge userbase produces a warning. Don’t panic! Mostly this happens after a new version of JPEG Repair or JpegDigger has been released. After enough users ran the software, the warning might vanish, because it now has reputation. If you see a SmartScreen warning, you can safely click ‘More info’, then ‘Run anyway’.
Same may happen in your webbrowser. It may warn about an unknown or not very commonly downloaded file. This is due to the fact that after each update the file is new.