1. Check your connections (check whether the player says it's charging when you plug it in)
2. Double check you have the device set to MTP(a lot of sansa's menus like to pretend to have set something when all it really did was open a different part of the menu)
3. Double check MB is set to "Detect MTP devices"
4. See if Windows Media Player can find the device. If so, check if you can see it under "My Computer". If you can see it under "My Computer" and MB still does not "see" the device (on the left under computer most devices) then it may actually be a bug in MB(in which case I'm sure Steven will want more information