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Win 10 20H2 transparency not working with 3D acceleration

Posted: 17. Apr 2021, 16:28
by VirtualIan
Host: VirtualBox 6.1.18 r142142 (Qt5.14.2) on Ubuntu 19.10 host, Nvidia GTX 1050 Ti graphics, Nvidia 460 binary drivers.

VirtualBox settings: display VBoxSVGA with 3D acceleration ticked.

Working guest: Windows 10 1909 edition, 6.1.18 VirtualBox extensions installed - fine until upgraded to..

Problematic guest: Windows 10 20H2 edition, 6.1.18 VirtualBox extensions installed - with default Windows settings, main menu background appears for a second, then goes fully transparent. The taskbar is transparent from the start.

Unticking transparency effects in Windows or unticking 3D acceleration in the options in the host stops the problem, but something's not right. I am not enough of a Windows nut to know if Win 10 1909 had transparency effects or not, but the main menu and the taskbar appeared fine.

Re: Win 10 20H2 transparency not working with 3D acceleration

Posted: 17. Apr 2021, 17:04
by mpack
VirtualIan wrote:I am not enough of a Windows nut to know if Win 10 1909 had transparency effects or not
Regardless, the problem with Windows transparency effects appeared with Win10 2004, not with a particular version of VirtualBox.

Re: Win 10 20H2 transparency not working with 3D acceleration

Posted: 18. Apr 2021, 15:56
by VirtualIan
So it's been an issue since the first half of 2020 ?!?

I know the video drivers are 'experimental', but I would say that this is a bit embarrassing for Oracle.

Re: Win 10 20H2 transparency not working with 3D acceleration

Posted: 18. Apr 2021, 17:44
by mpack
VirtualIan wrote:I know the video drivers are 'experimental', but I would say that this is a bit embarrassing for Oracle.
These are user discussion forums. If you have a support complaint then you need to take it up directly with your Oracle rep. Assuming of course that you can demonstrate that the problem is definitely with VirtualBox and not Windows (since build 2004).

Re: Win 10 20H2 transparency not working with 3D acceleration

Posted: 18. Apr 2021, 20:35
by VirtualIan
You tell me it's a problem that's been known about for months, so I'm not going to add a '+1' to wherever (or whatever) the official support for an experimental feature on a free product is.

It works if I don't enable 3D acceleration on the host, and it works if I'm not on an emulated machine. If that doesn't point to it being a VirtualBox issue around its video driver not supporting whatever functions Windows is calling properly when doing 3D acceleration, then what would?