Microsoft emergency updates fix RDS failures

Microsoft has released emergency out-of-band updates on September 14 to repair failures in Remote Desktop Services (RDS), the Windows feature that lets people and administrators connect to a computer or server over a network. The problems were introduced by the September 2026 security updates and caused unreliable Remote Desktop Protocol (RDP) connections, sign-in failures, and in some cases unresponsive servers. The patches also address two additional issues on certain Windows versions: a Hyper-V folder-sharing problem and a USB audio multichannel bug.

The September security updates destabilized RDS on affected systems. After administrators reported widespread RDS problems, Microsoft acknowledged the issue. Beyond failed remote connections, related tools could stop responding, including Microsoft Management Console (MMC), the RDS Licensing Diagnoser, File Explorer, and even the Windows Update page itself. Microsoft had provided temporary Group Policy mitigations, which are centrally configurable rules administrators can apply, but those were not a permanent fix.

The emergency updates released on September 14 cover a range of Windows versions. For Windows 10 21H2 and 22H2, Microsoft released KB5129236. Windows 11 24H2 and 25H2 receive KB5129195, and Windows 11 26H1 receives KB5129194. On the server side, Windows Server 2019 gets KB5129238, Windows Server 2022 gets KB5129237, and Windows Server 2025 gets KB5129235. Microsoft says the server patches specifically address the RDS failures introduced by September's KB5122871 on Windows Server 2025 and KB5122882 on Windows Server 2022. The Windows 11 26H1 update, KB5129194, is available through 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 emergency patches are available through the Microsoft Update Catalog. Administrators who removed the September security updates reported that Remote Desktop worked again, but that rollback also removed the security fixes those updates provided, so the emergency patches offer a way to restore RDS without losing that protection.

The Windows 11 emergency updates also fix two other issues. One is a Hyper-V problem affecting applications that use Host Compute Service (HCS)-managed virtual machines. Some applications could not properly share Windows host folders with Linux virtual machines using Plan9, a network file-sharing protocol, causing the shared folders to not appear inside the guest environment or to become inaccessible. The other fix targets an audio issue with some USB Audio Class 1.0 devices, a common standard for USB sound hardware. In standard stereo mode these devices worked normally, but they could fail when switched to multichannel configurations such as 8-channel or 3D audio modes.

Microsoft warns that the emergency updates do not resolve all of the USB audio problems introduced by the September updates. According to the release notes, after installing the September 8, 2026 security update some USB Audio Class 1.0 devices might fail to start or produce sound. Affected devices may show "This device cannot start (Code 10)" in Device Manager, which is the Windows tool that lists hardware and errors. Other symptoms include no audio output, volume controls that are unresponsive or stuck at zero, and sound settings that are unresponsive or unavailable. Microsoft says this remaining problem is limited to USB Audio Class 1.0 devices and that a fix is being worked on.

For website owners, businesses and IT teams, this story is a reminder that security updates and stability fixes often travel together. RDS outages can block access to servers that host websites, control panels and internal applications, so applying the correct emergency patch quickly matters. Before rolling out an update, it is wise to back up critical systems and test on a small group, especially when the fix arrives outside the normal schedule. For teams that manage Windows servers and Remote Desktop Services in production, AEU-I provides security-first IT, infrastructure and consulting support that can help with patch management, testing and backup planning before emergency fixes are deployed.