I've been have a hard time playing the HD version of my iTunes content for tv shows. I think it started around the latest iTunes update. I get a box that says the computer is not authorized (it is) and then a grey box. It is playing (I can see the time counting by) but there is no picture or sound. I've tried deauthorizing and reauthorizing, deleting the SC info, and removing some codecs people have suggested. I sent a request to Apple a few days ago and heard nothing back. Because the content was playing on my iPhone, today I tried playing the standard definition version on my computer -- and that works. So it's only the HD version of the show that has problems. I've got the latest version of iTunes, and the most updated mac OS. Any suggestions?