If your desktop is 1024×768 or 1200×800 most likely you want a Virtual OS to be 800×600. Most Linux distributions will allow for resolution adjustment, but sometimes X gets in the way. X is designed to maximize the resolution based on settings in the xorg.conf file. The simple solution to your desktop resolution problem is: sudo nano /etc/X11/xorg.conf Delete any reference to a resolution other than “800×600″. Now when X wants to maximize your resolution the 800×600 will be the maximum available.