It really sounds like you are scanning to the hard drive of the machine instead of the USB drive. However; I would contact your nearest support center for additional assistance.
As in subject scan to usb stores documents on printer instead on usb. When usb stick is taken out the files dissappear, but when any other usb stick is inserted all the documents can be seen again. Unfortunately this results in that I can see other people's documents by selecting and printing them. The documents are not stored on the usb stick itself.
It was ok before, but dont know what happened.
printer: xerox workcentre 7545.