Virus-based FTP.
We covered in your first Resnet training session.
Regardless, have you ever seen Windows do that all by itself?
Virus is much more likely than a corrupted partition table.
I try to avoid reformatting. I know you liked to but it’s a hassle for the user and you jumping straight to formatting is just as bad as me jumping to virus. Only if I’m right there’s alot less reinstalling required.