I have a 500 GB USB-disk which has been used as a backup device for a few years now, but now fails without telling me why.
This is a Dell box with Intel USB-controllers (so the NVIDEA problem does not apply here). I have previously had problems with a Git package marking a non-existent directory for backup (adding it make the backup succeede). The inaccessible boot partition problem described in Windows Backup fails with 0x80070002: "The system cannot find the file specified" does not apply to me.
I would appreciate hints on where to look to identify why my backup fails so I can fix it.