OK, so I have three Apple TV's, got them about a month ago. They've been working great. Tonight, all of a sudden, the all exhibit the same odd behavior. I turn on my iMac, load iTunes, and they all 3 show up. Then within 1 minute, they all disappear. If I try to sync one of them before they disappear, I get the message: "The Apple TV <name> is not responding. Check that any firewall software running on this computer has been set to allow communication on port 3689." None of my setting have changed at all, I checked my firewall in Leopard and it's set to allow incoming connections (even tried resetting those settings). I've tried rebooting both the iMac, all the Apple TVs, and the Airport Extreme Base Station multiple times, and nothing works. If I try to play a movie on one of them before they disconnect from iTunes, it will play for about 60 seconds before it disconnects from iTunes. I can play YouTube on it after it disconnects from iTunes so I know it's still connected to the network. One is hardwired to the AEBS, two are wireless. I'm running iTunes 7.6.1. I also tried reverting one of them back to 1.1 and the same thing happens. Also tried repairing permissions on my iMac, but still get the problem. EDIT: OK, I figured out that the problem is my iMac. All the Apple TV's sync and stream just perfectly with my MacBook iTunes library (iTunes 7.6 - NOT 7.6.1). So, something in my iMac changed by itself in the last 24 hours, or there's a problem with 7.6.1. Also tried reinstalling iTunes 7.6.1. I tried repairing permissions and tried setting up a new iTunes library. Tried copying iTunes 7.6 from the MacBook to the iMac. FrontRow works on the MacBook reading the iMac library. Nothing has worked... Anyone have ANY idea what's causing this or how to fix it??? Is there any way to revert back to 7.6? I'll call Apple tomorrow to see what they say.