Out of no where today A LOT of my songs in iTunes have exclamation points next to them and will not play. I got the new rMBP on the day it was released and transferred songs over then. At that point, I went through my library and tried to delete duplicates. I realize this could be part of the issue, but I only deleted DUPLICATES, not ALL the songs on an album. Now, I have quite a few full albums that won't play at all. No idea what happened. I did upgrade iTunes/OSX recently, but I feel like this can't be the issue. Or is it?