Microsoft has issued urgent out-of-band Windows updates to address failures in Remote Desktop Services (RDS) that were triggered by this month’s security updates, as well as issues related to Hyper-V and USB audio on certain Windows versions.
The security updates from September 2026 led to instability in Remote Desktop Services (RDS) on affected systems, resulting in failures in RDP connections and sign-ins, and in some instances, servers becoming unresponsive.
Microsoft had previously recognized the problem after reports from Windows administrators indicated widespread RDS issues following the September updates.
Systems impacted may also face difficulties with associated components and tools, such as Microsoft Management Console (MMC), RDS Licensing Diagnoser, File Explorer, and the Windows Update page, which could become unresponsive.
On September 14, Microsoft released several out-of-band updates to rectify the issue, including:
- Windows 10 21H2 and 22H2: KB5129236
- Windows 11 24H2 and 25H2: KB5129195
- Windows 11 26H1: KB5129194
- Windows Server 2019: KB5129238
- Windows Server 2022: KB5129237
- Windows Server 2025: KB5129235
The updates for Windows Server address RDS failures that were introduced by the KB5122871 update on Windows Server 2025 and KB5122882 on Windows Server 2022.
While working on a permanent solution, the company had previously offered Group Policy mitigations for the affected Windows and Windows Server systems.
Administrators also noted that uninstalling the September security updates restored Remote Desktop functionality, although this action removed the security fixes included in those updates.
The Windows 11 26H1 update, KB5129194, can be accessed via Windows Update, Windows Update for Business, the Microsoft Update Catalog, and Windows Server Update Services (WSUS).
For Windows Server 2019, Windows Server 2022, and Windows Server 2025, the out-of-band updates are available through the Microsoft Update Catalog.
Additionally, Microsoft released KB5129195 for Windows 11 24H2 and 25H2, as well as KB5129236 for Windows 10 21H2 and 22H2 to tackle the RDS failures affecting those systems.
Hyper-V and multichannel audio issues
The out-of-band updates for Windows 11 also address a Hyper-V problem impacting applications that utilize Host Compute Service (HCS)-managed virtual machines.
According to Microsoft, some applications encountered issues when sharing Windows host folders with Linux virtual machines using Plan9, resulting in shared folders either not appearing in the guest environment or becoming inaccessible.
The updates also resolve an audio issue affecting certain USB Audio Class 1.0 devices when used with multichannel audio, including 8-channel and 3D audio modes.
Microsoft states that while affected devices functioned normally in standard stereo mode, they could fail when switching to these multichannel configurations.
However, the emergency updates do not fix all USB audio issues introduced by the September updates.
“After installing the September 8, 2026, Windows security update, some USB Audio Class 1.0 devices might fail to start or produce audio,” Microsoft notes in the release documentation.
“Affected devices may exhibit one or more of the following symptoms: An error in Device Manager stating, ‘This device cannot start (Code 10),’ no audio output, unresponsive volume controls that remain at zero, and unresponsive or unavailable sound settings. This issue is confined to USB Audio Class 1.0 devices.”
The company is currently working on a solution for the remaining audio issues.
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Source: Original article
