John wants to recover some data off a USB Thumb drive. Leo recommends RECUVA or PC Inspector for Windows. On the Mac, Leo recommends Data Rescue. It's not free though. But the fact is, when flash memory dies on a USB drive, it's pretty much dead. And if it doesn't mount, it's completely shot. The only option at that point is to take it to a professional and that would cost far more than it is worth.