Many times when I sync my Iphone5 to my Itunes and I come back to find half my music deleted. This doesn't happen all the time but it seems quite often . . . Very frustrating as often times I need to wait hours so phone can "resync" all the songs that have seemingly been deleted. Again, its never all songs but a significant chunk. Sync entire music library is checked as well as Sync only checked songs/videos Please help. . .