This method will only work from a Mac computer. Before you do this fix, you need to back up your files on the mp3 player because they will get deleted in the process of the fix.
Step 1: Finding "Disk Utility".
Open your finder. Click on the applications tab on the left.
Step 2: Open Utilities
Open "Disk Utilities".
Step 3: Select the Mp3 Player.
Step 4: Erase Tab
Click the erase tab.
Step 5: Reformating
Select the "MOS-DOS (FAT)" option on the pull down tab that says "format".
For the name, type in what you want the mp3 player to be called.
Step 6: Security Options
Click the "security options" button. Slide the slider all the way to the right. Click "Ok".
Step 7: Erasing
Click "Erase". It might take a while, depending on how many files are on the player. Wait until it is finished. Then go to your desktop and eject the disk.