A couple of weeks ago, my Sansa Clip Zip started to act strangely. Intersperse between the regular songs were accented a symbols, squares, and chinese symbols. If any of these items were selected the device would freeze. However, after formatting the device it would work fine again, until the strange files started to appear again. Now, my Clip Zip will function while plugged in to the computer (shows to be connected, can add and remove files, etc.) but when it is disconnected from the computer it will either immediately crash, hang on the Sansa logo, or hang on the “refreshing your media” screen after reaching a low point on the loading bar. Formatting the device has not fixed the problem now. Any help?
By any chance, is the player’s USB mode, under Settings, set to MTP mode or to Auto (which will try to use MTP mode)? MTP mode can cause display issues. MSC mode, in contrast, just seems to work trouble-free (and will work with everything but DRM’ed files). You might try reformatting to clear all the content off your player and then try wth the player set to MSC.
And if you can’t reformat from the player, can you format from your computer, e.g. using Windows?
Finally, you might also try manually reapplying the latest firmware (see the firmware upgrade sticky thread at the top of the forum), in case some firmware glitches have crept in.