Cannot format - Creative Technology ZEN Stone MP3 Player

From: http://www.anythingbutipod.com/forum/showthread.php?t=31068

1. Connect the player to the computer.
2. Double-click the My Computer icon on the Desktop.
   If the My Computer icon is not on the Desktop, click Start and My Computer.
   If the My Computer icon is not in the Start Menu, right-click the Start button and click Explore.
3. Locate and right-click the disk drive listed as ZEN Stone or ZEN Stone Plus followed by a drive letter.
4. Select Format.... File Context Menu Click to enlarge
   
5. Ensure the File system is set to FAT or FAT 32. Leave the remaining options set to the defaults.
6. Click Start.
7. Re-transfer the files back to the computer.

If resetting or formatting doesn't help, you could also try reloading the firmware. Connect the Stone, download the firmware, and then execute the the firmware file.

1. With the Stone disconnected, download and install the Player Recovery Device drivers.
2. Download the Stone's firmware from Creative's site.
3. Boot up the Stone as a Player Recovery Device (also see below).
4. Connect the Stone to the computer and let it load the driver (see here).
5. Execute the downloaded firmware file or Creative's Recovery Tool.

Sometimes, in order to install the firmware, the Stone needs to be connected as a Recovery Device:

1. Make sure the Stone is disconnected and turned off.
2. Press and hold the volume down button.
3. Continue to hold the button until you have performed Steps 4 through 6. If you accidentally release the button, start the procedure again.
4. Press and hold the Power/Pause/Play button
5. Hit the reset button
6. Connect your player to your computer's USB port and after 5 seconds, release both buttons.
7. Once the Stone is recognized, execute the old firmware file.
Hope this helps, and have a nice day! ^_^