Administrators report Remote Desktop Services failing after September 2026 updates
Multiple Windows administrators report that this month's cumulative Patch Tuesday updates for September 2026 are triggering Remote Desktop Services (RDS) failures on production servers. Reports collected on Reddit and directly to BleepingComputer describe environments where RDS works normally for a few hours after installation, then begins to fail: existing sessions refuse to disconnect or log off, new connection attempts hang during the connection process and eventually fail, and in many cases the only recovery has been a hard reset of the server.
Affected Windows Server releases and KB numbers
The problem is reported across several supported server releases. Administrators cited failures on Windows Server 2019, Server 2022, and Server 2025 installations after installing the September cumulative updates identified by these KB numbers: Server 2019 (KB5122876), Server 2022 (KB5122882), and Server 2025 (KB5122871). BleepingComputer has received reader reports and Reddit threads tying the outages to this month's Patch Tuesday cumulative updates.
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End the scrambleObserved behavior, debugging clues, and what is not confirmed
Operators describe consistent symptoms: session drops, inability for sessions to properly log off, new logons that hang and time out, and, in some cases, services that become unresponsive and require a full server reboot. One administrator said restarting the server did not resolve the problem, but rolling back the September update did restore Remote Desktop functionality.
One Server 2022 investigator reported a debugging trace that pointed to the RDP service hanging at a symbol named RDPSERVERBASE!WDLIB_Close and described what appeared to be a deadlock between Remote Desktop and the Local Session Manager (LSM). That diagnostic observation was posted by an administrator on Reddit; Microsoft has not confirmed the deadlock hypothesis or identified a cause.
Rollback as a mitigation, and its trade-off
Administrators who removed the September cumulative updates report that rolling back the updates restores RDS functionality. However, removing the updates also removes the security fixes that Microsoft distributed as part of this month's Patch Tuesday—creating a direct trade-off between restoring remote access and retaining the bundled security patches.
What this means for IT administrators, enterprises, and remote workers
- IT administrators and technologists: Teams must weigh the operational need for remote access against the security posture lost by uninstalling September fixes. Several admins reported servers functioning normally for hours before the failures began, so monitoring session activity after patching will be necessary to detect onset.
- Enterprises and procurement leaders: Organizations that rely on Terminal Servers or pooled RDS environments face potential disruption that, according to reader reports, can require physical access to the server to perform a hard reset. That raises continuity and access-planning concerns for offsite operations and third‑party hosts.
- Remote workers and end users: Users may experience dropped sessions and inability to reconnect after logouts. In reported cases, the problem sometimes appears only after the first user logoff following patch installation.
Microsoft's response and the open question
BleepingComputer contacted Microsoft to ask whether the company was aware of the reported Remote Desktop Services problems and whether a fix or mitigation was available. At the time of publication, BleepingComputer had not received a response. The published reporting says the outlet will update the article if Microsoft provides additional information.
The facts on the table are straightforward and consequential: administrators across multiple Server releases report that September 2026 cumulative updates can render RDS unreliable or unresponsive; rolling back the updates restores access but removes security fixes; and a debugging post points to a possible deadlock between Remote Desktop and the Local Session Manager, a diagnosis Microsoft has not confirmed. Until Microsoft publishes guidance or a corrected update, organizations that depend on Terminal Services must choose between degraded remote access and lingering unpatched vulnerabilities—or pursue mitigations that balance those risks.
