Auto-Resize Guest Display Grayed Out on Windows 10 Guest (Ubuntu 20.04 host)

[openminded]

VirtualBox 6.1.8
Host: Ubuntu 20.04
Guest: Windows 10
Hardware: Lenovo Thinkpad P1
Graphic Cards: Nvidia Quadro T2000 (discrete graphics always on, no switchable graphics)

Hi,

I think problems started when I updated to Ubuntu 20.04 (not really sure). Option "Auto-resize Guest Display" is disabled / grayed out. Max. resolution is 1920x1200 but I have a 4k Monitor (3840x2160). So that is not satisfying.

Guest Add-Ons are installed, of course. Tried to update to the newest ones. Already tried to set "Graphics Controller" from VBoxSVGA to VBoxVGA (as suggested by some users). Did not help.

Any suggestions?

best regards,
Markus

[scottgus1]

Start the guest from full normal shutdown, not save-state. Run until you see the problem happen, then shut down the guest from within the guest OS if possible. If not possible, close the Virtualbox window for the guest with the Power Off option set.

Right-click the guest in the main Virtualbox window's guest list, choose Show Log. Save the far left tab's log, zip it, and post the zip file, using the forum's Upload Attachment tab.

[multiOS]

One thought: If there are greyed-out entry in the display entries in the View menu, this ususally means that the Guest Additions weren't fully installed and there should have been warning message in the Ubuntu Terminal app along the lines of "This system is not currently set up to build kernel modules" with further guidance on what needs to be done. It's a Linux thing you just have to get used to!

[openminded]

Please find the Logfiles attached.

One thought: If there are greyed-out entry in the display entries in the View menu, this ususally means that the Guest Additions weren't fully installed and there should have been warning message in the Ubuntu Terminal app along the lines of "This system is not currently set up to build kernel modules" with further guidance on what needs to be done. It's a Linux thing you just have to get used to!

I think Guest Additions are installed properly. Indeed, setting screen size to 1920x1200 was only possible after installing Guest Additions (1024x768 before). So, they seem to work somehow.

I can start virtualbox via console. There is no output on stdout/stderr. Where to find your warning messages?

[multiOS]

Sorry, my mistake I'd read this as Ubuntu on Windows and not Windows on Ubuntu! Stupid error on my part.

[scottgus1]

I see that Guest Additions are installed. Unfortunately that is all I could guess about.

Windows 10 will probably need the VboxSVGA card, especially if you had 3D acceleration checked. VboxVGA no longer has 3D acceleration.

[openminded]

Hi,
I finally found a solution. VBoxVGA works! However, you have to shut down your guest properly by the operating system itself. If shutting down the guest by "Power off the machine", resizing is disabled.

Not having 3D Acceleration is a drawback.

Recently, someone added this issue to the Bug Tracker. See my comment there. https://www.virtualbox.org/ticket/19593

best regards

[hdingari]

I had a fresh install of Ubuntu 20.4 on Windows Host and the screen size of the guest OS (Ubuntu) was fixed and not resizing when the window is being resized. When I clicked on the bottom right of the Guest OS Frame where the display icon is, it was showing the "Auto-resize guest display" as greyed out.

Here is how I was able to make it work:
Go to the top of the window menu bar. Go to Devices, Select "Insert Guest Additions CD Image", don't worry, it doesn't really need any CD. After that it will ask you restart/reboot the guest OS. After the reboot, the auto-resize should work.

-HD