Sansa Clip+ MP3-Player >> "Not enough space for music DB. Please free 90MB."

I finally got past this and found a fix.  I held down the power button until it got to the message “Refreshing your meida.”  That task never couldn’t complete, so the player stayed on until the battery failed.  Then I attached the Clip Player to a USB port on my Windows 7 PC.  Amazingly the PC once again recognized it as a valid device, and, from Windows Media Player I was able to reformat it  After that it worked normally again.