Instability in Remote Desktop Services following September's security releases prompted Microsoft to distribute emergency patches across multiple operating system versions on September 14. The failures manifested as RDP connection problems, sign-in errors, and in certain cases, unresponsive servers running affected systems.

Beyond RDS complications, the September updates introduced problems with dependent systems and utilities. Users reported that Microsoft Management Console (MMC), RDS Licensing Diagnoser, File Explorer, and the Windows Update interface became unresponsive on impacted machines.

Microsoft had previously acknowledged the widespread RDS disruptions after administrators flagged the issue. While developing a permanent solution, the company distributed Group Policy workarounds to mitigate the problem on affected systems.

The emergency patches released on September 14 include:

  • Windows 11 26H1: KB5129194
  • Windows 11 24H2 and 25H2: KB5129195
  • Windows 10 21H2 and 22H2: KB5129236
  • Windows Server 2025: KB5129235
  • Windows Server 2022: KB5129237

The server-focused patches target RDS failures introduced by KB5122871 on Windows Server 2025 and KB5122882 on Windows Server 2022 during the September rollout.

Distribution channels vary by product. The Windows 11 26H1 patch is accessible via Windows Update, Windows Update for Business, the Microsoft Update Catalog, and Windows Server Update Services (WSUS). Server editions receive their patches exclusively through the Microsoft Update Catalog.

Some administrators had discovered that removing the September security updates restored RDS functionality, though this approach eliminated the security protections those patches provided.

Hyper-V and multichannel audio fixes

Beyond RDS remediation, the Windows 11 emergency patches address a Hyper-V problem affecting applications leveraging Host Compute Service (HCS)-managed virtual machines. When sharing Windows host directories with Linux guests via Plan9, shared folders either failed to display within the guest or became inaccessible.

The patches also tackle an audio malfunction impacting certain USB Audio Class 1.0 devices in multichannel configurations, including 8-channel and 3D audio modes. These devices functioned normally in standard stereo operation but encountered failures when switching to multichannel settings.

The emergency updates do not fully resolve all USB audio complications introduced by the September patches. Microsoft notes that additional work remains to address the complete scope of audio issues.

After installing the September 8, 2026, Windows security update, some USB Audio Class 1.0 devices might fail to start or produce audio. Affected devices might experience one or more of the following symptoms: The device displays an error in Device Manager: "This device cannot start (Code 10)." No audio output. Volume controls are unresponsive or remain at zero. Sound settings are unresponsive or unavailable. This issue is limited to USB Audio Class 1.0 devices.

Microsoft