I have Ubuntu 14.04.1 installed as a virtual machine on my 2011 Macbook Pro, on Parallels 9.0.24251. I downloaded the Ubuntu iso file from the Ubuntu site 2 weeks ago. It works perfectly. However, in the normal process of using 'sudo apt-get update', and the GUI sofware update app, Ubuntu downloads a lot of stuff that is more recent than the install iso. When I reboot the VM after the update, the login screen is normal, but after loading the GUI, any new window gives a black screen (with dashes and lines in some cases). All the dock applications generate black screens, although the dock icons themselves are normal. Same is true for the menu bar controls. The MBP has a Radeon 6770m/Intel hybrid graphics set up. So I presume Ubuntu has downloaded the wrong graphics driver, but it's not clear which of the update files is causing the problem. I checked the "Additional Drivers' option and there is nothing available, but I suspect Parallels has its own drivers which are being damaged by the Ubuntu update. Is there a way around this problem? Additional info: I did the system test suite and the grapgics driver version test reported the following: ERROR: No video driver loaded! Possibly in failsafe mode! ------------- VIDEO DRIVER INFORMATION ------------- ------------- HYBRID GRAPHICS CHECK ---------------- Graphics Chipset: Unknown (1ab8:4005) Loaded DDX Drivers: prlvideo Hybrid Graphics: no The prlvideo DDX reference suggests it's Parallels doing the video, in which case Ubuntu should not interfere, or there should be a way to reinstall the Parallels driver. Is there?