VirtualBox 6.1.6 r137129 - Window Size Resets to 800x600

[dbergst]

While running a virtual machine, i.e., Kubuntu 20.04, after installing the current guest additions, the window size of the VM resets itself to 800x600 pixels. This reset consistently occurs even if higher resolution is selected. Attached is a log from this VM in case that is any help in resolving this issue.

Note - I have run into this issue also with the Linux release so the comments here apply as well to that release.

[Mannekino]

Same issues. It's getting really annoying that there is a massive issues with each upgrade. Now I have to go back again two versions.

[dbergst]

As a workaround I downloaded and installed the guest additions from VirtualBox 6.1.4. No window resize issues occurred after that.

[Richlv]

Having it reset to 800x600 with OpenSUSE Tumbleweed, MacOS host. Virtualbox 6.1.8, guest packages from OpenSUSE.

[mobc]

Hi,
There is a known bug/problem in KDE Plasma, that can be fixed manually:
" KDE Plasma5 can't change resolution in VM..." . Here is the bug report link:
https://bugs.kde.org/show_bug.cgi?id=407058
The bug report also has the fix for the problem inside the comments.
The KDE developers don't have time to solve this bug, so users will have to wait or fix the problem themselves.

To fix the problem you have to disable KScreen2.
To enable changing the resolution in PCLinuxOS live iso inside Virtualbox, here's what I did:

I disabled KScreen2 from Start Menu > Background Services > Startup Services and then I increased the display resolution from 800x600 and the change was persistent.
The resolution didn't immediately reset to 800x600 if KScreen2 is disabled. Even if KScreen2 is enabled but its Status is "Not Running", the resolution cannot be changed, so make sure to disable KScreen2.

I expect the fix will work with VMWare, too.