VirtualBox "Auto resize guest display" greyed out

Question

I have a virtual machine on VirtualBox (version 6.0.6), guest system CentOS 7, host system Windows 10. Extension pack is installed. Graphics controller is VBoxVGA.

I followed the steps here for installation of VirtualBox Guest Additions (no errors displayed) and reboot.

On CentOS:

> systemctl -t service | grep vbox
VBoxadd-service.service   loaded active running VBoxadd-service.service

(that means guest additions are running). "Auto resize guest display" is still greyed out.

About current kernel:

> sudo uname -r
3.10.0-957.12.2.e17.x86_64

• This Q and A does not help in my case.
• This one does not explain how to get auto-resize working.
• This is not helpful as I already installed guest additions.
• This one not provide solution.

Note that on the same host, Fedora 30 virtual machine and Ubuntu 14.04 virtual machine "auto resize" properly works.

Update: still happens with VirtualBox 6.0.8 (updated Extension Pack and Guest Additions too).

Any hint? What I'm missing?

Answer 1

I had a similar issue (didn't read all of your references though, short on time) and for me it worked with 3D acceleration enabled and grafics controller VBoxSVGA. Noting else changed.

I am on version 6.0.12 on the host and the additions are 6.0.14.

Answer 2

My solution was to set the display to VBoxVGA (VirtualBox 6.1.6 r137129 Qt5.9.5, Guest additions installed, Debian 10)

Answer 3

Running VirtualBox as a superuser (or Administrator in Windows) resulted with ungrayed “Auto resize guest display” button, thus solving the issue for me.