Hey guys,
I'm only posting this here because I had the same problem with a previous macbook and had to reinstall the OS to get them to work. Well I came across the problem once again with a different different Macbook! In iTunes, I can't get any of my videos, all purchased from the iTunes music store and authorized under my account, to play with audio. I'm thinking it's a Quicktime issue, I have the most current version, all my audio outputs seem to be ok...and all my songs play perfectly fine. Totally weird. Anyone else having this issue??? Anyone know how to fix it???