I can't seem to find a solution to this particular problem so far. I'm desperate, I have NO music, NO ringtones and just one or two default notification sounds. This happened yesterday, suddenly and I haven't installed any new apps to explain this behaviour. I can't seem to play any kind of music file. I've tried the stock music player, Google Music Play and a couple random music players from the play store... and they all either crash and close or show me a "cannot play file message". I deleted all the music files (mp3) and tried with new files, I tried playing them from the SD card and from the internal memory and the result is the same.