Windows 8.1 DWM crash and black screen (0x8898009b)

[Vic Lee]

Steps to reproduce:

1. Host running Windows 8.1 or 2012r2 with all updates
2. Guest running Windows 8.1 (fresh install) with all updates
3. Guest set to use 2 vCPUs
4. Boot and login to desktop in the guest
5. Mount/unmount an iso file repeatedly from the GUI "Devices" menu

When performing step 5 DWM will crash several times and then the screen is completely black. The only way to restore is VM hard reset. The event viewer shows several such DWM error logs:

The Desktop Window Manager has encountered a fatal error (0x8898009b)
Log Name: Application
Source: Desktop Window Manager
Event ID: 9020

Please also note that it won't happen when using only 1 vCPU; and I actually found a workaround by changing the system boot argument:

bcdedit /set useplatformclock true

The issue seems to a CPU clock issue, and should has nothing to with the iso mounting itself. The iso mounting just somehow trigger the bug.

[cremor]

Maybe related ticket: #13088

[aeichner]

Please reopen if still relevant with a recent VirtualBox release.

[RolfW]

This issue is back again since I upgraded to Virtualbox 7.0. Host and client: Window 10 x64, latest uopdates. Frequent dwm.exe error 0x8898009B with a black scren triggered by an interaction (mouse or keyboard).