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I'm trying to run Windows 8 in VirtualBox. My laptop's display is exactly 1366x768. Windows 8 disables some of its features if the resolution is less than 1366x768, so I need to run the guest OS fullscreen.

The problem is, VirtualBox refuses to run the guest at 1366x768. When VirtualBox is "fullscreen", the guest is only 1360x768 -- six pixels too narrow. So there's a three-pixel black bar at the left and right sides of the display.

This user had the same problem, but the accepted answer is "install the Guest Additions", which I've already done; that got me to 1360, but not to 1366.

According to the VirtualBox ticket tracker, there used to be a bug where the guest's screen width would be rounded down to the nearest multiple of 8, but they claim to have fixed the bug in version 3.2.12. I'm using version 4.1.18 and seeing the same problem they claim to have fixed, so either they broke it again, they were wrong about ever having fixed it, or my problem is something else entirely.

This answer suggested giving the VM 128MB of video memory, and claimed no problems getting 1366x768 afterward. When I created the VM, its display memory was already defaulted to 128 MB. I tried increasing it to 256MB, but with no effect: the guest is still six pixels too narrow.

My host OS is Windows 7 64-bit, and I'm running VirtualBox 4.1.18.

How can I get VirtualBox to run my guest OS fullscreen at my display's native resolution of 1366x768?

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Did you bother installing Guest Additions on the guest? That's one of the things it's there for. –  b1nary.atr0phy Mar 3 at 0:05
@b1nary.atr0phy, as I said in the question: the accepted answer is "install the Guest Additions", which I've already done. –  Joe White Mar 3 at 0:19

6 Answers 6

While the VM is running, you can also tell the guest OS to change the resolution by using:

VBoxManage controlvm "Name of VM" setvideomodehint 1366 768 32

The 32 at the end denotes the display color depth.

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Worked for me, thanks! –  Edward Ruchevits Jul 30 '13 at 16:41
Exact same problem here, but with a Win7 guest -- and this solution also worked. So did turning off the VirtualBox 3D acceleration as advised here: superuser.com/a/443733/26903 –  Stabledog Oct 4 '13 at 18:11
This isn't working for me, please help. I'm running ArchLinux, KDE. My VM is listed in VBoxManage list runningvms But unable to change resolution from 800x600 to 1280x1024 –  Ravi Dhoriya ツ Mar 24 '14 at 21:13
up vote 4 down vote accepted

After burning an entire weekend on this, I finally found the culprit: VirtualBox's 3D acceleration.

If you go into your virtual machine's Settings > Display, and uncheck "Enable 3D Acceleration", then the guest will successfully run at 1366x768.

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This worked for me with a Win7 guest. And so did this solution: superuser.com/a/586538/26903 –  Stabledog Oct 4 '13 at 18:15

I had it working by doing this:

  1. Shutdown VM

  2. Navigate to C:\Program Files\Oracle\VirtualBox\

  3. Shift + Right-Click > Open command window here

  4. Run command VBoxManage.exe setextradata "Windows 8 RTM Evaluation" CustomVideoMode1 1366x768x32

  5. Start VM

  6. Launch Desktop, Right-Click > Screen Resolution

  7. Choose 1366 x 768

But, it broke...

I updated VirtualBox and installed new Guest Additions. Now it's using "VirtualBox Graphics Adapter for Windows 8" and I cannot select a wide resolution.

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I figured out how the guy from Indonesia did it and managed to make it work , but on Win XP guest OS . Should probably work for Win 8 just as well .

  1. You must have the VB guest additions installed on host OS

  2. Start the VM and from the mini toolbar , right click on CD/DVD and select "Choose a virtual CD/DVD file" .

  3. When prompted , browse to VB installation folder and select the VBoxGuestAdditions.ISO

  4. Setup will start running on your guest OS and will install the VB guest additions

  5. Restart and it works even with 3d video acceleration enabled .

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I recently experienced the same problem. Fortunately, for me I was able to fix my resolution issues by using this link: https://www.youtube.com/watch?v=KCSXDjKKaQo . I followed the instructions step by step and now everything is functioning perfectly. The guy on the video is using a MAC to access the terminal which would make the changes to the screen resolution. I'm using Windows 7 to access Command Prompt (CMD). Interestly enough, the commands work on both Terminal and CMD.

As a FYI make sure to use "1366 768 32" exactly how Oliver's posting described

Hopefully this helps.

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Make sure that your hardware supports whatever resolution you intend to use.

Boot your Linux guest in VirtualBox and press c in the GRUB menu (it's a blue screen in Debian) and then in the grub> prompt use the vbeinfo command to check the supported resolutions by your hardware. It's in the format of 1366x768x32.

Press Esc to exit grub> prompt and proceed. Then:

  1. login to the system as root
  2. vim /etc/default/grub
  3. edit, using one of the modes supported:

  4. update your Grub configuration (the command in Debian is update-grub, and in OpenSUSE is grub2-mkconfig -o /boot/grub2/grub.cfg)

  5. log out
  6. in Windows (or whatever the host OS) run this command:

    C:\>...\vboxmanage setextradata "your_guest_os_name" "CustomVideoMode1" "1366x768x32"
  7. reboot your guest OS

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