How to get Ubuntu guest VM to recognize second VirtualBox monitor?

Solution 1:

I finally figured out how to get it working - I had to install:

sudo apt-get install virtualbox-ose-guest-x11

...and restart. The VM didn't boot the first time, but a hard reset seemed to sort things out.

Note: at first, Natty assumed I wanted to clone the displays... but a quick trip to System->Preferences->Monitors was able to fix that.

Solution 2:

Multiple monitor setup of Virtual Box requires the installation of Guest Additions in the guest OS.

Mostly depending on the graphic card there may still be some issues with Virtual Box and Compiz/Unity in 11.04. Make sure you download and run the most recent version of Virtual Box.

If Unity/Compiz still won't run you can try to run Ubuntu 11.04 in a multiple monitor setting by choosing Ubuntu Classic Desktop (no effects) on login.