I got a 25 foot HDMI cable so I could hook to my TV from across the room. My desktop shows up fine, but goes to black every few seconds, and comes back. The picture looks fine while it is running. I am wondering if the length of the cable is causing it to drop out? This is a 2011 MBA ultimate. ---------- Just tested this on a '09 13" macbook pro, worked fine. No dropout or anything. Something about the MBA doesn't like the setup. Maybe it's the thunderbolt port not liking the HDMI adapter? Anyways, this really sucks. Bought all that cable for nothing. ---------- Also - it appears to go black every 8 seconds, exactly.