On my test installations of Ubuntu 14.04 in VirtualBox, I had to figure out how to deal with a situation where the highest screen resolution I could get is 640 x 480. And it was not just with Ubuntu 14.04, but also with Kubuntu 14.04.

When I ran the xrandx command, the output was:

kamit@HU:~$ xrandr
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 640 x 480, current 640 x 480, maximum 640 x 480
default connected primary 640x480+0+0 0mm x 0mm
   640x480        73.0*

Here's what it looks like from the Display module of System Settings.


That's not good.

I found that there are two solutions to the problem.

1. Use Xdiagnose

From the Dash, search for and launch Xdiagnose, then enable all the options under Debug. Click the Apply button, then close the window and restart the system.

2. Additional Drivers

Also from the Dash, search for and start Software Updates. Click on the Additional Driverstab, then click on the Using x86 virtualization solution.... Apply the changes, then restart the machine afterwards.


With either solution, the system should reboot in 1024 x 768 screen resolution, and you should be able to expand the window simply by dragging it. And if you run the xrandxcommand, the output should be:

kamit@HU:~$ xrandr
Screen 0: minimum 64 x 64, current 1024 x 768, maximum 16384 x 16384
VBOX0 connected primary 1024x768+0+0 0mm x 0mm
   1024x768       60.0*+
   800x600        60.0  
   640x480        60.0