I updated my virtual box hosted ubuntu from Ubuntu version 20.10 to 21.04. Upon update, the Ubuntu is no longer in full screen.

Host: "20.04.2 LTS (Focal Fossa)" Virtualbox version: Version 6.1.16_Ubuntu r140961

I checked all the guest additions, x11 etc.. on the guest OS (V 21.04) all the good things still remain.

Please help get back the full screen.

Thanks in advance.

1 Answer 1


Reinstall Guest Additions on the VM. It's possible that it was corrupted during the upgrade, or a version mismatch could have occurred after upgrading. I recently ran into this issue upgrading the Host, and the culprit was the version of Guest Additions installed on the VM was not supported by the version of VirtualBox on the host.

  • Thank you. I uninstalled virtualbox components in the guest, re-installed. Then, on the host, downloaded lastest guest additions iso, then, on the guest, inserted the iso again, then boom... it worked. Thank you for suggestion. Commented Apr 29, 2021 at 13:57

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