I have an Acer S211HL monitor. I also have a MacBook Air 2011 with a Dynex MiniDP to DVI adapter. It used to work a week or two ago, and now it doesn't work! The screen on my Mac will flash blue for a second like it's going to work when I plug it in. Then the monitor just says 'NO SIGNAL'. If I used the same adapter and same monitor with my rMBP it works perfectly! I can also use my Dynex MiniDP to VGA adapter, and it works fine. But I'd really like to know why the other adapter quit working out of the blue.