I am using a 2011 MBP 17" laptop,with 8gb RAM and a 750GB hd. Yesterday morning I had recently updated my Mac OS software. This morning I was going to use my iMovie which was working without a problem. However on clicking on the app, I get a pop up that states: iMovie requires a graphic card compatible with Quartz Extreme. One or more of your cards does not support Quartz Extreme. I never had this problem before. It used to work flawlessly. what's up with this? Anyone else encounter this?