Microsoft Issues Emergency Windows 11 Update to Fix Record Patch Bugs

Microsoft released an emergency out-of-band update for Windows 11 on September 14, 2026, to address critical bugs introduced by its record-breaking security patch issued just one week earlier. The September 8 Patch Tuesday update addressed 966 security flaws, including two actively exploited zero-day vulnerabilities, but it also caused significant instability for some users. The emergency patch, designated KB5129194, targets Windows 11 versions 26H1, 25H2, and 24H2. It resolves issues with Remote Desktop Services, which had become unstable and prevented new sessions, and fixes problems with folder shares in Hyper-V-based Linux virtual machines. The update also addresses some, but not all, USB audio device failures. According to Microsoft, the emergency update fixes failures involving multichannel audio, but some USB Audio Class 1.0 devices may still fail to start or produce sound. The company stated it is working on a fix for those remaining issues. The update is cumulative and can be installed without first applying the September 8 patch. The original September 8 update was notable for its scale, patching a record 966 vulnerabilities across Microsoft products.