Microsoft (MSFT) Ships Emergency Windows 11 Fix, AMD GPU Bugs Remain

Microsoft Corp. (NASDAQ: MSFT) shipped an emergency out of band update for Windows 11 on 15 September, a week after a Patch Tuesday release that fixed a record number of vulnerabilities and broke a broad set of systems in the process.

The September update, KB5124008, addressed 974 vulnerabilities, the largest Patch Tuesday Microsoft has issued. Security researchers counted 119 critical entries, with 723 affecting Windows components and 111 affecting Office.

The emergency patch, KB5129195, is mandatory and cumulative, advancing Windows 11 25H2 to build 26200.9457 and 24H2 to 26100.9457. It fixes Remote Desktop Services instability, multichannel audio failures covering 8-channel and 3D modes, and folder sharing problems with Linux virtual machines. It also completes a fix for CVE-2026-62721, an elevation of privilege flaw in the Windows User-Mode Power Service that the September update did not fully resolve. Windows 10 versions 22H2 and 21H2 receive a separate update, KB5129236.

Several problems remain open. Crashes affecting AMD Radeon graphics drivers are not addressed, with users reporting driver timeouts, black screens, missing displays and system freezes that reinstalling drivers does not resolve. Explorer.exe crashes continue, concentrated in enterprise environments running Citrix UPM, FSLogix, Horizon or ProfileUnity. File History has stopped detecting external drives for some users, and certain USB Audio Class 1.0 devices still produce no sound.

Hardware specific reports have surfaced on HP systems, where the update has been linked to BIOS corruption, and on Lenovo machines showing unexpected black screens or shutdowns.

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