To quote member Shiltz, from the following thread: http://www.anythingbutipod.com/forum...ewreply&p=3788
Originally Posted by shiltz
In MSC mode the player is a USB mass storage device and shows up under my computer as a drive letter and can be used just like any drive can be, and you can stick music anywhere you want on it and the player will play it, however everytime you unplug the player from the computer it reads everything on the player too recreate it's database of music.
In MTP mode it shows up as what looks like a little mp3 player icon called Sansa e2x0, you can still drag and drop music but only into the media\music folder, but it automaticaly updates the database realtime as you add or remove stuff so you can unplug and use it right away without the database refresh which can get very long with lots of stuff on the player. MTP mode is I belive also needed for transfering using media player and for putting on any DRM "infected" mp3's from the online places you can buy them from.
Sorry, but I don't know anything about Media Source. As for knowing which mode you are in, simply press the "Home" button (looks like a house in the upper right corner), choose "Settings", then USB Mode. There are three choices, "Auto Detect", MSC, and MTP. Being the control freak that I am, I like to manually choose. That way, I KNOW what mode I'm in. And in case you are in "Auto Detect" and you're wondering what mode your computer has chosen for you, simply open Windows Explorer and check your drives. If the clip shows up as an additional drive (ie with a drive letter assign to it), then Windows is using it as a mass storage device (like a flash drive). This means it's in MSC mode. I used to use MSC mode, however when you add tracks or update playlists, it tends to take a very long time, so now I'm using MTP. Well, that and the fact that I couldn't get MSC to work with playlists.. ; )
How that helps!