Microsoft has released emergency out-of-band updates for various Windows versions to address critical issues, including Remote Desktop Services (RDS) failures, Hyper-V problems, and USB audio malfunctions. These issues were introduced by the security updates deployed earlier in September 2026.
The September security updates caused widespread instability in Remote Desktop Services on affected systems, leading to failures in RDP connections and sign-ins, and in some instances, rendering servers unresponsive. Microsoft had previously acknowledged these problems following numerous reports from Windows administrators. Related components such as Microsoft Management Console (MMC), RDS Licensing Diagnoser, File Explorer, and the Windows Update page could also become unresponsive on affected systems.
The new out-of-band updates, released on September 14, are intended to resolve these issues. Specific updates include KB5129194 for Windows 11 26H1, KB5129195 for Windows 11 24H2 and 25H2, and KB5129236 for Windows 10 21H2 and 22H2. For server environments, KB5129235 addresses issues on Windows Server 2025, while KB5129237 targets Windows Server 2022. These server updates specifically fix RDS failures caused by KB5122871 on Windows Server 2025 and KB5122882 on Windows Server 2022.
Prior to the release of these permanent fixes, Microsoft had offered Group Policy mitigations for affected Windows and Windows Server systems. Administrators also found that uninstalling the problematic September security updates restored Remote Desktop functionality, though this action also removed the security patches included in those updates.
The new updates are available through various channels. KB5129194 for Windows 11 26H1 can be obtained via Windows Update, Windows Update for Business, the Microsoft Update Catalog, and Windows Server Update Services (WSUS). The out-of-band updates for Windows Server 2022 and Windows Server 2025 are accessible through the Microsoft Update Catalog.
Beyond RDS, the out-of-band Windows 11 updates also address a Hyper-V issue impacting applications that utilize Host Compute Service (HCS)-managed virtual machines. Some applications experienced difficulties when attempting to share Windows host folders with Linux virtual machines using Plan9, resulting in shared folders either not appearing or becoming inaccessible within the guest environment.
Furthermore, the updates resolve an audio problem affecting certain USB Audio Class 1.0 devices when operating in multichannel audio modes, such as 8-channel and 3D audio. While these devices functioned normally in standard stereo mode, they could fail when switching to multichannel configurations.
However, these emergency updates do not resolve all USB audio problems introduced by the September updates. Microsoft has stated that some USB Audio Class 1.0 devices may still fail to start or produce audio after installing the September 8, 2026, security update. Symptoms can include a "This device cannot start (Code 10)" error in Device Manager, no audio output, unresponsive volume controls, or unavailable sound settings. This specific issue is confined to USB Audio Class 1.0 devices, and Microsoft is actively working on a further fix for the remaining audio problems.
