Microsoft Rushes Emergency Windows 11 Fix After Record Patch Breaks PCs

Microsoft rushed out an emergency, out-of-band update for Windows 11 this week after its September security release, the largest of the year, broke Remote Desktop connections, audio on USB devices, File History backups and Windows Explorer for a swath of users, while leaving a separate wave of AMD graphics-card crashes unresolved.

The trouble began with the September 8 Patch Tuesday release, which addressed 611 unique security flaws in Windows 11 alone, part of a Microsoft-wide update fixing more than 960 vulnerabilities across its products, according to an analysis by Computerworld. Two of the flaws, in the Windows Update Stack and in Advanced Local Procedure Call, were already being exploited before the patch shipped, and Microsoft Office received 22 critical fixes, a dozen of which could be triggered simply by previewing a malicious file with no click required.

Fixes that created new problems

Alongside those security repairs, the update introduced regressions that Microsoft has spent the past ten days chasing. Remote Desktop sessions began dropping after a few minutes of use. Multichannel and 8-channel USB audio failed on some systems, and other machines lost sound entirely. File History stopped detecting external backup drives. Windows Explorer crashed to a black screen immediately after sign-in on some configurations, and AMD Radeon graphics cards, including the RX 6600, 7700 XT, 7800 XT, 7900 GRE, 7900 XTX and 9070 XT, began freezing or throwing driver timeouts.

Microsoft's response, an out-of-band patch labeled KB5129195, arrived September 15 and brought affected machines to build 26200.9457 on Windows 11 25H2 and 26100.9457 on 24H2. It restored Remote Desktop connectivity, addressed part of the USB audio failure and fixed a folder-sharing bug affecting Linux virtual machines running under Hyper-V. It did not fix complete audio loss on some devices, microphone failures, File History's backup detection, Explorer crashes in enterprise environments, or the AMD graphics-driver errors that have generated the loudest complaints on enthusiast forums.

Microsoft has not published a timeline for a further fix to the AMD issue, which affects a broad slice of the current Radeon lineup and has left some gamers and creative professionals reverting to earlier driver versions or delaying the update altogether. The company has acknowledged the bug internally but has not said whether the fault lies in its own code or in AMD's driver stack. Windows 10 machines still receiving paid extended security updates were affected by a smaller, overlapping set of the same regressions and received their own out-of-band fix alongside the Windows 11 patch, according to PCWorld's reporting on the rollout.

The episode underscores a pattern that has become more pronounced through 2026: security patch volumes have grown sharply even as Microsoft's testing has struggled to keep pace with the scale of what it ships each month. September's release surpassed a previous high set in July, when the company also needed a follow-up fix within days, and IT administrators managing large fleets of business PCs have increasingly taken to delaying Patch Tuesday updates by a week or more to let early problems surface before rolling them out broadly. For most home users, Windows Update will apply KB5129195 automatically; those still waiting on an AMD fix are being advised by hardware forums to hold off on updating GPU drivers until Microsoft or AMD issues further guidance, and to check Microsoft's release-health dashboard before applying any pending update on machines running Radeon graphics.