I've a 512MB pen drive and have been having strange problems with it. Whenever I copy whole folders on to it, the files are there until I remove the drive (or restart the computer with the drive still plugged in), and then the folder remains, but it's empty. The really strange thing is that pre-existing folders still contain their files, and that files copied onto the root of the pen drive don't disappear. I've tried various manipulations to make sure that everything is written to the drive before I remove it, and I've confirmed the files really are there on the drive in the first place by opening them directly from the pen as soon as I've copied them. Thinking it sounded like a FAT problem I reformatted the pen, and now it seems to be working OK, BUT I was wondering if anyone else had experienced these sorts of problems. In particular I did not experience this issue until I had a lot of files in a lot of folders, so I wondered if the FAT can get full if it's stored in a dedicated, limited part of the pen. Things that count against this are the fact that when I deleted a number of folders, the problem persisted until I reformatted the drive, and that there has never been a problem with files on the root of the drive.
this was an ebay purchase, from a UK seller but the manufacturer is an obscure chinese outfit, so my chances of redress are slim - if I can understand what's going wrong I hope to be able to work within those limitations rather than consigning it to the scrapheap.