After wake up my 2011 mid iMac , and click on quictime video on apple site, or youtube video another sites, the iMac crash, but any graphics program (angry birds, wow) working properly. No mouse, just a freezing screen. After restart with power button, everything is working fine the next wake up. This is known problem, or my new iMac failure? update: if i start video with mplayerX after wake up, everything is fine. I think mplayerX do something after wake up iMac, that correct this video failure.