Microsoft has confirmed that its September 2026 security updates can cause Remote Desktop Services (RDS) to become unstable, potentially disrupting remote access to Windows PCs and servers. The issue has been reported across multiple Windows versions and can leave administrators unable to connect to affected systems.
RDP Connections Can Suddenly Fail
The problem may not appear immediately after installation. In affected environments, Remote Desktop connections can work normally before failing after several minutes. Users may encounter sign-in failures, while servers can become stuck at the “Please wait for the Remote Desktop Configuration” screen.
The issue can also affect related administration tools. Microsoft has reported cases where Microsoft Management Console, RDS Licensing Diagnoser and File Explorer become unresponsive. Even the Windows Update interface may stop responding and remain stuck on a loading screen.
Windows Server Versions Affected
The problem has been associated with September’s cumulative security updates for Windows Server 2012 and laterincluding Windows Server 2019, 2022 and 2025. Certain supported Windows 10 and Windows 11 versions are also affected.
For administrators managing remote infrastructure, the failure is particularly disruptive because RDP is often the primary method used to remotely access and troubleshoot servers.
Microsoft Releases Emergency Fixes
Microsoft has already started releasing out-of-band updates to address the RDS problem. For example, KB5129237 fixes the issue on Windows Server 2022, while KB5129238 addresses it on Windows Server 2019.
Microsoft’s release-health documentation describes the issue as mitigated or resolved for systems covered by the relevant emergency updates.
Before those fixes became available, Microsoft suggested that administrators dealing with inaccessible virtual machines could temporarily stop or deallocate and then restart the affected machine to restore RDP connectivity. However, this approach can cause service interruption and was not considered a permanent solution.
Security Updates Created an Access Problem
The incident highlights a difficult situation for IT teams. The September updates were released as security patches, meaning organisations cannot simply ignore them because of the RDS regression.
Administrators therefore need to balance security patching with remote-access availability, particularly for production servers that depend heavily on RDP for management.
Summary
Microsoft confirmed that September 2026 Windows security updates could cause Remote Desktop Services to fail, resulting in broken RDP connections, sign-in problems and unresponsive servers. The company has released emergency out-of-band updates for affected Windows versions, providing organisations with a permanent path to resolve the issue.
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