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I am a heavy VirtualBox user. I run VirtualBox on a Windows 7 host and mostly Windox XP guests...but some linux and others as well.

When using my Windowx XP guests, I REALLY miss the multi-monitor support you get when not in a VM.

I would love to be pointed to some step-by-step instructions for getting this to reliably work for my Windows XP guest VMs.

Any thoughts?


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If you're using Virtualbox 3.2.x or 4.x, this feature is available out of the box, with no complicated setup. From this question:

Basic Setup:

  1. Power off your virtual machine if it's on.
  2. From the main VirtualBox window, select your VM and choose Settings.
  3. Choose display.
  4. Below "Video Memory" is Monitor Count. Slide it to 2, and adjust 1. your video memory if VirtualBox complains.
  5. Start your guest and perform the standard "Extend the desktop onto 1. this display" method based on the Guest OS. (Guest Additions need to 1. be installed.)
  6. A second "Oracle VM VirtualBox" window will appear with the second display. You can resize it however you want.
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This worked beautifully for me and gives me the "truest" dual monitor experience (versus resizes the guest window). – Ryan Taylor Feb 19 at 20:21

You could try using Seamless Mode and just place the individual virtualized application windows on your existing multi-monitor setup.

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+1 for the greatest idea! I never thought about this, and I'll try it as soon as possible. Very clever, I really hope that will be TEH hit! – dag729 Dec 25 '09 at 5:30
+1 this worked for me, thanks! – Daniel Schaffer Mar 14 '11 at 23:53

You can try the suggestions from this thread (only works with XP guests):

Effectively using Virtualbox with Dual-Monitor-Host

Or (and this the easy way out) simply resize the VirtualBox and span it over two monitors (but do increase the shared video memory).

enter image description here

(View bigger)

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Boo! Who wants to use the easy and logical way to span 2 monitors! I prefer overly complex solutions – Jared Harley Dec 23 '09 at 1:28
yep, complex solutions are great ... IF you get them working! :D – Molly7244 Dec 23 '09 at 1:38
I do this all the time. Since my win-7 taskbar is only on my left monitor, I snap the VM window to the left screen edge, and drag the right edge to the far right. Only annoyance is that many dialogs pop to the screen center and so get split by the bezels. – Peter LaComb Dec 23 '09 at 12:45

It looks like multiple monitors are only supported for the VBoxHeadless Frontend. According to the VirtualBox User Manual:

VirtualBox allows the guest to use multiple virtual monitors. Up to sixty-four virtual monitors are supported.


  1. Multiple monitors currently work only with Windows XP guests, and Guest Additions must be installed, as the implementation resides in the Guest Additions video driver.
  2. Multiple monitors work only with the VBoxHeadless frontend. You must also enable VRDP multiconnection mode (see the section called “VRDP multiple connections”) to access two or more VM displays when the guest is using multiple monitors.
  3. The guest video RAM size should be increased when multiple monitors are used. The VRAM is shared among the virtual monitors so that only part of it is available for each one. Therefore the available resolutions and color depths will be reduced if the VRAM size remains the same and multiple monitors are enabled.
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I don't think this information is correct any longer. Your link is broken - here is a link to the relevant info for v4 – Goyuix Mar 15 '11 at 14:15

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