I just updated the kernel on my Ubuntu 20.04 LTS to 5.8-0-34-generic. Now my Ubuntu no longer opens full screen, opening with 800 x 600 resolution rather than the 1920x975 pixels available on my display, with no option to increase screen resolution. Fortunately I had a clone still running the 5.4.0-59-generic kernel, which continues to work correctly.

I'm running Ubuntu 20.04 LTS in a VirtualBox (Version 6.1.16 r140961 Qt5.6.2) virtual machine, original Linux kernel 5.4.0-59-generic, upgraded to new kernel 5.8-0-34-generic. The system graphics card is an NVIDIA GeForce MX 330. Further exploration reveals that the problem probably results from an incompatibility of the virtualbox-guest-dkms 6.1.10-dfsg-1~ubuntu1.20.04.1 package. I have submitted a problem report to debian.org, which appears to be the source of the package, and I have submitted the problem to the VirtualBox community help site.

I'll follow up here if I get a response from VirtualBox community help.

  • Does the old kernel show it properly? – FelixJN Jan 6 at 17:38
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    Can you please edit your question and add more details of what your system is like Video card, motherboard, etc. we should be able to help more. What this does sound like is that you have an NVIDIA card that you might have installed the drivers direct from NVIDIA that don't have DKMS drivers with them that get carried over to new kernel updates. – Terrance Jan 6 at 18:08
  • Unless you really need the 5.8 kernel, reboot, and select the 5.4 kernel as a temporary fix. – Archisman Panigrahi Jan 7 at 11:59
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    You are installing Guest Additions a wrong way. They should be 6.1.16. Install from Device menu of the VB machine. – Pilot6 Jan 8 at 8:43

Run in the virtual machine

sudo apt purge virtualbox-guest-dkms

Then install Guest Additions form the Device menu of the virtual machine.

It will install the 6.1.16 additions that are compatible with the 5.8 kernel.

The Guest Additions in Ubuntu repos were not updated. It is not a problem of VirtualBox developers, but by Ubuntu maintainers.


I got the same issue, just upgrade VirtualBox and extension pack then it should working again.


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