well my wife put folders with sub folders onto the thing and that was the start of my problems. I could not get the unsupported files deleted by hitting delete or trying to delete them via the computer through usb connection. I finally got tired of trying and just figured i would hit "delete all" and just reload the music i erased. I was so wrong! well now the player is still being regconised by my computer, but i cannot add any files or make new folders or anything. It says the directory or file cannot be created. it gets even stranger still. When i check the properties for the drive it says i have 2.88gb used and 1.10gb free space. that makes me believe i bought a hacked piece of junk. when i turn the device on and try to pull up the music,movies,picture sections it just shows a blue screen that says disc empty. The tuner and games still work fine. I will list my firmware version if it helps. This is a pic of the exact player i have and the name of the company i got it from so everyone can see that you might not want to get one from these guy's off of ebay.
BKSD91N12_32
2007-11-01
9.1.52
2005-01-09
If anyone has had a similar problem could you please let me know how you fixed it!