Okay I've been having a problem in recent months. When I hit play in iTunes, nothing happens immediately. The play symbol does change to pause, but there is no sound. After 5-10 seconds, the music begins. I can pause and resume immediately, but an extended stop will result in the same delay sequence. Video playback is also affected. The picture starts and 10 or so seconds later, the sound starts. Anyway I can't figure out what is going on, so I took it in and left it at the local apple store. This is a 2008 mac pro running ML BTW. After 3 days of inpatient care at the store, I get the call. The "genius" tells me that they can't perform the standard testing and diagnostics because there are "third party" parts in the Mac Pro. He worries that if they damage a component, they can't replace it with a stock item, so they won't do anything. YOU HAVE GOT TO BE KIDDING ME!! Is there a Mac Pro on the planet that does NOT have third party parts in it? Of course it has an aftermarket USB 3.0 PCI card in it, that is what expansion slots are for! I have already explained that my issue has been present through two OS X versions, two different video cards, multiple hard drive configurations, a memory upgrade, and other hardware changes. The problem clearly does not care about said hard parts. Anyway I've lost some faith in the Genius Bar and still have my problem. Are YOU smarter than an Apple Store Genius?