I placed microsoft briefcase on a removable flash drive. I use the drive between work and home. At work I use the drive on several computers. All of the computer I use have XP. Two or three times the briefcase has "vanished" off the drive. The files remain on the drive but the briefcase "shell" disappears and the files cannot be updated. The briefcase seems to disappear at work when i try to save a file into the briefcase. This does not always happen though. Any thoughts on what causes this behavior?