Hi Guys, having a frustrating problem. I connect 2x 27" 2560x1440 Hazro monitors via 2 USB Dual Link DVI to Mini DisplayPort Adapters. They were working fine but have now stopped! The monitors display a blank screen, the Mac clearly switches to the external displays, the displays appear in the preferences and I can move them around, the mouse pointer disappears off the side as though going to the extra space. Just NO picture! I have tried connecting a MacBook Air and that works so I know the monitors and adapters are fine. I have shut down the Mac and rebooted, with and without the cables attached. I removed GFXCardStatus to no effect. Anything else I can try? I did install Steam in between using the external monitors but I cant see how that would cause an issue. Do you think the Thunderbolt ports could have blown?