Ubuntu – Use Ubuntu graphical desktop without monitor at boot

12.04bootvgawindows xpxorg

I have two computers: one running Windows XP and one running Ubuntu 12.04. They are connected to my monitor via a VGA switchbox. What I would like to do is be able to boot Ubuntu without a monitor, but then be able to switch back to it, and still have a graphical desktop running. I have read about creating a headless Ubuntu server, but the guides I have found all seem to involve disabling the graphical session altogether. How can I set this up?

EDIT:

My Ubuntu computer is a HP Pavilion a1120n.

Best Answer

Ubuntu has a great "FEATURE" (ok, it actually sucks) that disables/stops booting your system (and/or) graphical system if there is no monitor. The devs weren't smart enough to allow the system to remember the last monitor attached and/or switch to a different display automatically if you start headless and then attach a different different monitor than before.

This post will help you out (best I can do):

How to remove the graphical user interface?

Look for the answer with lots of updvotes.

You can also do this if that answer doesn't work all the way:

Create an override file for you display manager in /etc/init/ and place the word 'manual' in it. So if you have 'lightdm' you would create a 'lightdm.override' with the single word 'manual' in it, and put it in the '/etc/init/' directory. You will need to use 'sudo' to create and edit the file. Same with the grub file in the link I provided.

You can start the xserver/GUI manually:

sudo service lightdm start

and to stop it:

sudo service lightdm stop
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