I can't get my Mini Display Port to HDMI to work in OS X but it works fine in Windows. This is driving me mad. The OS X knows it's there and I can change the resolution and move the mouse to the other monitor but nothing shows up on my other monitor. It just stays asleep the whole time. In windows it works 100% of the time both at the same time with no problems at all. Note: I have a iMac 21.5 3.06 i3. (2010)😡