You now have to back up your USB drive before you try to recover anything. You can do this in Disk Drill. Go to Extra Tools, ...
Why copying and pasting isn't a real backup: The danger of 'silent' data corruption ...
The silent data corruption problem that can destroy your files ...
The corruption has spread, and one of you is going to become a monstrous killer. The rest need to do everything in their power to complete all the tasks and escape. If you need any help in this ...