Full screen resolution incorrect in VNC

[gewe]

Hello,

When I connect to a running VM using VNC (noVNC, Remmina or RealVNC), the display resolution in full screen mode is wrong.
With a Windows 10 guest I get 1897 x 1091, with a Linux Mint 17.3 guest I get 1900 x 1088 (16:9). My monitor is 1920 x 1200.

When I run the exact same VM's on my desktop computer (the disk images are on an iSCSI target, I just copied the VM's definition), the full screen resolution is correct.

In the Windows 10 VM running in VirtualBox on NAS4Free, the list of possible screen resolutions is:

Code: Select all

1920 x 1440
1897 x 1091
1600 x 1200
1400 x 1050
1280 x 1024
1280 x 960
1152 x 864
1024 x 768
800 x 600

Why is 1920 x 1200 missing, and why is there such a strange resolution of 1897 x 1091 in the list?

Before I switch to fill screen, and when I switch back to non-full screen the resolution of the VM's display does not change, and I end up with scroll bars.
It is nice to be able to run VM's where their disk images are (for performance reasons), but my current experience is a bit mixed.

I asked this question at the VirtualBox forum, where someone pointed me to a thread where the proposed solution was:

Usually the display size you're stuck in is the highest possible 4:3 ratio, because VirtualBox and the Window guest have gotten tied into a knot telling/asking each other only about 4:3 ratio options, because that's the size of your default virtual monitor (your actual monitor of course isn't relevant to the VM). If you shut down all VMs, then in the UI go to File|Preferences|Display and set MaxGuestDisplaySize to "None" then you should be able to select any display size you like in any VM.

In phpVirtualBox under Preferences there is no Display section.

Since NAS4Free is using a fork of VirtualBox, at the VirtualBox forum they can not help me further. I hope someone here can help me solve this problem.

Regards,
George

[maddes8cht]

You can access these settings via comandline.

The main tool is the command vboxmanage

https://www.virtualbox.org/manual/ch08. ... -controlvm

First of all, to use the vboxmanage command in nas4free you need to follow this tip:
viewtopic.php?f=102&t=11799
I have set an alias for this:

alias vbox /usr/local/bin/sudo -u vboxusers /usr/local/bin/vboxmanage

so, the command to list all vms becomes
vbox list vms


Now read this section in the VirtualBox documentation (9.8. Advanced display configuration) , its just a short paragraph:
https://www.virtualbox.org/manual/ch09.html#idm7685



This may help with some guests, but, as pointed out in the section:

"When using Windows guests with the VirtualBox Guest Additions, a custom graphics driver will be used instead of the fallback VESA solution so this information does not apply."

So don't expect this to work with windows guests.

[gewe]

Thanks for your reply.
Unfortunately, since my pc is running Linux, I am only using VirtualBox for Windows guests.

[kenZ71]

I've had similar issues fixed by installing guest additions on the VM

[gewe]

I always install the guest additions. Video performance is terrible without them.