So here's the peculiarity… MacBook Pro, 16G RAM Core i7 Windows 7 VM, latest updates. The problem appears only to be with the Autodesk Inventor application. and it's repeatable... 1. boot the Mac (No external monitor) 2. start Parallels and start the Windows 7VM (either from suspended state or from shutdown). 3. Open Inventor and open any model display "has issues" Now, 4. quit inventor 5 PLUG IN A SECOND MONITOR 6. Start Inventor and open any model Display is perfect… 7. unplug the external monitor 8. quit inventor and re-open … Display is perfect…. So I believe this is really weird… it looks like I have to plug in a second monitor to get it working but then it's fine…. until I have to reboot.