virtualbox.org

I am trying to setup a Windows 10 (1809 x64) VM in Virtualbox 6.0.4 on a Linux Mint 19.1 (x64) host. Everything seems to be working fine for a little while, then several strange things start happening in the guest OS. Most notably I am not able to run anything as administrator. When a UAC prompt should show the screen gets dark as normal, then instead of showing the UAC prompt I get an error dialog like the one attached. This occurs when trying to run anything (not just the 7-Zip installer) as admin. When this starts happening I am no longer able to open the settings app (it opens the splash screen but immediately closes). Search also stops working in Cortona/Start.

It seems that switching the graphics controller from the default (VBoxSVGA) to VBoxVGA fixes the problem, but also means that I am left with a system with many more graphical glitches. I have the latest guest additions installed and have tried reinstalling several times. Any ideas as to why this would happen or how to fix it?

Note: The issue also occurs with a Windows 10 1803 x64 guest and on a Windows 10 (1803 x64) host. The host machine is always a Dell Inspiron 15-5570 with 8th gen i5 and 16GB RAM. The Windows 10 VM has 2 virtual cores, 256MB video memory, 4GB RAM, 60GB storage. 3D and 2D acceleration are enabled.

mb3l wrote:It seems that switching the graphics controller from the default (VBoxSVGA) to VBoxVGA fixes the problem, but also means that I am left with a system with many more graphical glitches.

I'm sorry, but where did that conclusion come from? The new VBoxSVGA is a foundation for better things to come. But which are not here yet.

The new one has a lot more glitches/kinks/artifacts/bugs compared to the old but trusted VBoxVGA one. It's simply that the foundation that the new model presents, is a lot more easier to fix issues, and a lot more easier to enhance its performance in the future, but not today. So, stick with what works, and in time you can keep on trying the newer VBoxSVGA one.

But thanks for the report, that's another thing that the developers will have to take a look into...

Moving to "Windows Guests" from "Linux Hosts", that's where the problem seems to be, in the guest...

socratis wrote:I'm sorry, but where did that conclusion come from? The new VBoxSVGA is a foundation for better things to come. But which are not here yet.

That conclusion is just based on my experience when using the OS with the SVGA and VGA adapters. It seemed to have more glitches with the older adapter than with the newer one.

However, that being said, when 3D acceleration is disabled (using either adapter) the glitches/artifacts are far less frequent.

Hi!

I have the same problem. Can not start any program that triggers the UAC dialog. The screen goes dim for a second (like in regular UAC operation), but then goes back to normal desktop and an error dialog appears saying, for example:

C:\Windows\system32\cmd.exe

One or more arguments are invalid

I use vbox 6.0.10 in Windows 8.1 Pro 64 bit.
guest is Windows 10 Home, 64 bit , vbox guest additions 6.0.8

I use this VM for a longer time and installed several apps that required the UAC. In other words: this used to work before.
What I changed is:
- vbox version (updated from older version to 6.0.10)
- made a snapshot of the VM (it had no snapshots before)

Turning off 3D and 2D Video acceleration in the VM Settings helps.

Looks a bug in the vbox virtual VGA HW, the guest additions driver or latest Windows 10.

After Windows 10 did it's daily update, it again works even with gfx accelerations enabled. So maybe it was a win10 bug.

Is there a ticket number where this is/was tracked?

@xerces8foo, FWIW while the devs are working the bugs out of the new video cards, you might try setting the UAC level on your guest OS to the "don't dim my screen" level, might help with the UAC prompt glitches.

In my case, Turned off 3D acceleration and installed normally when installing the Guest Ext Pack.