Windows 11 update KB5012643 also broke ancient DirectX 9 on "certain GPUs"

Microsoft has announced that its recent Windows 11 update KB5012643, which was already plagued with known issues related to Safe Mode and .NET 3.5, is now causing problems in games and applications that run on the DirectX 9 (Direct3D9) API. The Redmond firm says that the issues are happening on "certain GPUs" and no specific vendor has been mentioned, likely indicating that it is vendor-agnostic.

The bug is also causing Windows Event log errors pertaining to D3D9On12 mapping layer. Here is how Microsoft describes the issue:

After installing KB5012643, Windows devices using certain GPUs might have apps close unexpectedly or intermittent issues with some apps which use Direct3D 9. You might also receive an error in Event Log in Windows Logs/Applications with faulting module d3d9on12.dll and exception code 0xc0000094.

This problem also affects Windows 10 platforms, versions 21H2, 21H1, 20H2 (update KB5011831).

Microsoft is rolling back the updates on systems that are experiencing these issues using Known Issue Rollback (KIR). KIR is an important Windows servicing improvement to support non-security bug fixes, that enables reverting of buggy updates.

Resolution: This issue is resolved using Known Issue Rollback (KIR). Please note that it might take up to 24 hours for the resolution to propagate automatically to consumer devices and non-managed business devices. Restarting your Windows device might help the resolution apply to your device faster. For enterprise-managed, devices that have installed an affected update and encountered this issue can resolve it by installing and configuring the special Group Policy listed below. For information on deploying and configuring these special Group Policies, please see How to use Group Policy to deploy a Known Issue Rollback.

Group Policy downloads with Group Policy name:

Download for Windows 11, version 21H2 - Group Policy name: KB5012643 220509_20053 Known Issue Rollback
Download for Windows 10, version 2004, Windows 10, version 20H2 and Windows 10, version 21H1 - Group Policy name: KB5011831 220509_20051 Known Issue Rollback

Source: Microsoft (1 , 2)

Windows 11 update KB5012643 also broke ancient DirectX 9 on "certain GPUs"