A 4gb sanddisk went crazy on me when I had a Mogul coz I think i was rough on it ,taking it in and out without making sure process in pc was completely stopped, I spent sometime troubleshooting it, al kinds of formatting,locking and unlocking,putting tapes,using card readers,,pocket mechanic.....to no avail. .suggestion, eject safely, I got it replaced via their site support and all is well with it. Now I use an 8gb trans ...no prob