Before panicking, remember that even though your accounts are on the same server, your files may be on different physical machines in the SAN (storage area network). During the server changeover/config process, it was not uncommon to see the entire SAN become disconnected for brief periods, so it's tempting to think of the SAN as one big drive, but it's actually a whole bunch of disks in a whole bunch of machines, so it's possible for one account to lose connection to its files (or require restoration) while others maintain theirs. And it probably requires physical access to the SAN to fix, so it may take a while.