+ 0 Votes More than likely partition info got munged when Charles Bundy April 25, 2013 at 1:36pm PST unplugging the device w/o safe removal from OS. Like Col said find a good file system recovery tool or go to drive properties and try a fs fix. Sue T's suggestion depends on if the USB flash drive has been recognized by a second system. If the drivers get a fresh load file system check and fix is performed ( sometimes scan and fix pops up depending on fschk). Hope this helps!