Win10 Guest Using VboxSVGA is Black after Upgrade to VBox-7.0.10

[jagdpanther]

I have two Windows10 guest VMs both using VBoxSVGA graphics controller. One of them has a black display after I upgraded to VirtualBox-7.0.10 on my Linux host. The second Windows10 guest continues to work on the same Linux host without issue. (So I think there is an issue with the first guest.) The rest of this post is about the Windows10 guest with the black screen.

When booting the Windows10 guest, for a few seconds I see the regular Windows10 "icon" with the swirl below it. As soon as the Win10 guest VM window re-sizes (as it has always done) the resulting window is all black with no cursor or anything. The VirtualBox icons indicating network and disk activity continue to flicker as normal. I eventually kill the Win10 VM guest, revert to a known good snapshot. Then going into VirtualBox settings -> Display, I switch from VBoxSVGA to VBoxVGA graphics controller. The Win10 guest VM then boots and is usable. (I do receive a warning at the bottom of the VirtualBox settings window: "Invalid settings detected" as soon as I switch to VBoxVGA from VBoxSVGA)

How do I start using the VBoxSVGA graphics controller again in the Win10 guest VM? Are there issues with using VBoxVGA instead of VBoxSVGA graphics controller?

Notes:
1. I do NOT have "Enable 3D Acceleration" set.
2. When using VBoxSVGA switching to full screen changes the size of the all black Win10 guest window, to full screen but it is still black.
3. I have tried switching to VBoxVGA, booting the Win10 Guest, installing VBox guest additions 7.0.10 (upgrades from 7.0.8), shutting the guest down switching back to VBoxSVGA and booting the Win10 Guest: I still get the black screen.
4. My Linux host system is running Linux kernel 6.4.10.

[mpack]

Please provide a VM log file. Make sure the VM is fully shut down, then right click it in the manager UI. Select "Show Log" and save "VBox.log" (no other file) to a zip file. Attach the zip here.

[jagdpanther]

Attached is the log file.

[fth0]

You're probably experiencing a known regression:

If a VM has multiple virtual screens and the secondary screens are disabled, then the host will incorrectly disable the primary screen, too. As a workaround, either configure the VM with only one virtual screen, or enable the second virtual screen from the VM window's View menu.

This issue should be fixed in the VirtualBox test builds 7.0.11r158813 and newer.

[jagdpanther]

You're probably experiencing a known regression:

If a VM has multiple virtual screens and the secondary screens are disabled, then the host will incorrectly disable the primary screen, too. As a workaround, either configure the VM with only one virtual screen, or enable the second virtual screen from the VM window's View menu.

Yes, on this VM I enable 2nd screen within Win10 VM and then turn it off before I shut the VM down. I'll try you r suggested workaround tomorrow. Thank you.

[jagdpanther]

You're probably experiencing a known regression:

If a VM has multiple virtual screens and the secondary screens are disabled, then the host will incorrectly disable the primary screen, too. As a workaround, either configure the VM with only one virtual screen, or enable the second virtual screen from the VM window's View menu.

I confirmed that is the issue: I temporarily switched to the VboxVGA VM graphics controller, turned on the 2nd monitor within the Win10 VM, shut the VM down, switched back to VboxSVGA, and now the VM is working as expected.

[fth0]

Thanks for reporting back!