This also happened to me, except I didn't sync my songs. I have an application manager on my phone and it said my memory was low ans that I needed to restart it or something like that.. So I did and now when I try to play a song in my music folder it says 'cannot play media. Content is missing or unavailabe' and I also can't see the pictures I had before this happened. However, when I go on to my files manager, I can play the songs that I have recently downloaded and are on the download's page, but none of the songs that are in my music folder come up. And I have tried deleting them, but they just won't go. Any help?!!