On September 14, 2026, Microsoft released out-of-band emergency updates to fix failures in Remote Desktop Services (RDS) that appeared after the September security updates were installed. The issue caused RDP connections and sign-ins to fail and also made some servers unresponsive, while related tools and components such as Microsoft Management Console, RDS Licensing Diagnoser, File Explorer, and the Windows Update page were also affected.
Microsoft had acknowledged the issue after system administrators reported widespread RDS failures following the September updates. Before releasing the permanent fix, the company provided temporary workarounds through Group Policy. Administrators also reported that uninstalling the security updates restored Remote Desktop functionality, but at the same time removed the security fixes included in those updates.
Updates Available for Each Edition
The fixes include different package numbers depending on the Windows or Windows Server edition:
- Windows 10 21H2 and 22H2: update KB5129236.
- Windows 11 24H2 and 25H2: update KB5129195.
- Windows 11 26H1: update KB5129194.
- Windows Server 2019: update KB5129238.
- Windows Server 2022: update KB5129237.
- Windows Server 2025: update KB5129235.
The server updates address the RDS failures introduced by the September update KB5122871 on Windows Server 2025 and update KB5122882 on Windows Server 2022. The Windows 11 26H1 update is available through Windows Update, Windows Update for Business, the Microsoft Update Catalog, and Windows Server Update Services (WSUS), while the Windows Server 2019, 2022, and 2025 updates are available through the Microsoft Update Catalog. Microsoft also released fixes KB5129195 and KB5129236 for the affected Windows 11 and Windows 10 editions.
Additional Fixes for Hyper-V and Audio
The Windows 11 updates also include a fix for a Hyper-V issue affecting applications that use virtual machines managed by the Host Compute Service. Sharing folders from the Windows host with Linux virtual machines through Plan9 could cause the folders not to appear inside the guest environment or make them inaccessible.
The updates also fixed an issue affecting some USB Audio Class 1.0 devices when using multichannel audio, including eight-channel and 3D audio modes. The devices worked in normal stereo mode, but could fail when switching to multichannel settings.
What Does This Mean for System Administrators?
The emergency release provides an alternative to uninstalling the security updates, which is important for systems that rely on RDP for administrative or operational access. However, the fix does not cover every audio issue; Microsoft says that some USB Audio Class 1.0 devices may continue to fail or display Code 10 or lose audio after the September 8, 2026 update, and the company is working on a separate fix for these cases. Therefore, reviewing the update's compatibility with RDS and Hyper-V systems and audio devices before broad deployment remains essential, while noting that the source does not specify a date for the remaining fix.