I first noticed there was a problem when every time I plugged my device in and Rhapsody would freeze. I thought it was a Rhapsody problem. After many hours I realized it was a Sansa problem. It was saying “Not enough space for music DB…” and it would freeze Explorer (and my computer many times) Finally after hours on this board, I figured it out.
Open Disc Management. (For Windows 7 I clicked Start, and entered diskmgmt. msc into the search field)
Plugged in Sansa
Waited about 15-20 minutes and it finally showed up in Disc Management
Then I right clicked on (F: ) my device, and it froze. Waited another 20 minutes or so, and it unfroze.
Then I clicked Format, it froze. Waited another 20 minutes or so, it unfroze, and it was done!
I unplugged it and it is back to normal!
Hope this saves someone all of the hours I spent trying to figure this out. 
