One way to get Ubuntu running full screen is to hard-code the resolution of your monitor as a Linux kernel parameter. My monitor runs at 1680x1050, so I made the following changes to my Ubuntu 13.10 guest:
- Edit the grub configuration file, for example:
sudo vi /etc/default/grub
- Find the line starting with GRUB_CMDLINE_LINUX_DEFAULT, and add "video=hyperv_fb:1680x1050" (or your custom resolution) in between the quotes. For example:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video=hyperv_fb:1680x1050"
- Save and exit
- Restart your computer
If you get an error dialog warning about not being able to apply the video mode when logging into the GUI, use the Ubuntu control panel to change the screen resolution to your chosen custom resolution.