MSC doesnt work, MTP does

using “automatic detection” as usb service, my device is detected as mtp only. selecting usb service “msc” only, my pc freezes somehow (explorer etc freeze, not the whole of windows) - interrupting the connecting makes the pc work fine again

sometimes there are 2 drives in “my computer”, but both of them are inaccessable

 same issue testet on 3 pcs - any ideas?!

Just a guess, but maybe there is a bad file transferred via MSC. The computer doesn’t see it in MTP, so no crash .But when you switch to MSC, the bad file messes things up.

There are always 2 drives in MSC: internal memory and card slot.  If you have a microSD card in the unit, take it out, and see if MSC still crashes Explorer. 

The fix would be to put the unit in MTP, make sure you copy all your music elsewhere, and then Format from the Fuze menu (under Settings/System Settings). It’ll wipe out everything–including, presumably, the bad file. 

well, those mtp files cant be backup, can they?

and using mtp, i cant backup the other files as well…

I dont use a sd unit, only internal storage

Whether you can back up the files depends on the files–whether they were copy-protected or not.

Connect in MTP, find them by clicking in My Computer (or Computer) to explore the Sansa drive, and see if you can copy them. 

It is very strange not to have the MSC connection work.

Try this. Turning the unit off. Put the hold switch on (slide the power switch down until it clicks into place and you can see orange). Hold down the << button as you connect, and see if the Sansa pops up in My Computer.  

But if the MSC connection still crashes, and you have tried everything, then yes, those files will be gone when you Format.