Display shrinks to 1024x768

[Iain Waddell]

I've been using VirtualBox for several years but recently my Windows 10 guest upgraded from release 1803 to 1903. Since then I've had problems.

Initially I would have random lockups. Suddenly the guest would be unresponsive and after a while it would crash and VirtualBox would report that the guest had aborted. Googling led me to sites that suggested the lockups were usually related to the graphics driver.

I was using VBoxVGA (as I'd originally started on v5.1 of VirtualBox). After lots of reading about the VirtualBox video drivers I discovered I should have been using VBoxSVGA when I upgraded to v6.0 of VirtualBox (currently on v6.0.14).

Since the switch I've not had any lockups but at random times instead my desktop shrinks. I'm using a 4K monitor in Full Screen mode (3840x2160) and when the shrink occurs the Windows 10 desktop has shrunk to 1024x768 and is centred on the screen with a massive black border all around. The guest hasn't crashed and Host+F twice restores the screen to the full size but all my open applications have been squashed too, so I have to resize them.

I asked this question on the forums and it was suggested I log the problem here with logs.

When I originally reported the issue in the forums I was at home using my Windows 7 desktop but it's just occurred while I'm away running the VM on my laptop (Win 10 Home host).

Host: Windows 10 Home (Build 1903) Guest: Windows 10 Pro (Build 1903)

[Iain Waddell]

Logs and .vbox file

[sunlover]

According to the log the guest first disables the display and then resizes it to 1024x768. Is there any screensaver in the guest or the screen Power & Sleep setting is not set to Never?

It looks like the guest is doing this.

[Iain Waddell]

Screensaver: None Power & Sleep: Never & Never

[Socratis]

Related discussion in the forums: ​https://forums.virtualbox.org/viewtopic.php?f=6&t=95502

[frg]

I can confirm this even for Windows 7. Usually happens after startup. Windows 10 and Server 2016 are affected.