most of the time when that happens you can try one of two things one try going into window media player and sync you music to the player or go to "MY COMPUTER" and right click on the mp3 and click "FORMAT" then click ok LEAVE EVERYTHING LIKE IT IS in that window just click ok (you can name you device if you like) then click format let it do a compleat format then befor writeing music to the player unplug it and turn it on so that way it can write its files to the drive (only some players will do this other you will not need to but do it just in case) then plug it in and try to sync you music through windows media player if your on a mac you can just write the music files to the disk on the desktop. then your player should be all right if not then your player has been raped and its no good anymore try sending it in to get a replacement. if any of this was helpfull or you got more question please email me at cnvirus@live.com