I just had a tech support call the other day for a department that was not working. They had a contracted data entry project that needs assistance fairly quickly when a problem occurs.
It turns out that the supervisor for the area had been requested to clean up the files on the computer. So he did.
He moved some files into groups with the names of the files. Fortunately the fix was to move all of the files back into the directory he moved them from. (Right now he still has a job.)