Microsoft's September 2026 Patch Tuesday cumulative updates are breaking Remote Desktop Services on Windows Server 2019, 2022, and 2025, according to administrators who have installed them. Affected servers can run normally for a few hours before new connections begin to fail, and some machines have required a hard reset to become usable again. The reports, gathered from Reddit threads and from readers who contacted BleepingComputer, describe failures across all three supported Windows Server releases.
The specific updates tied to the reports are KB5122876 for Windows Server 2019, KB5122882 for Windows Server 2022, and KB5122871 for Windows Server 2025. Admins say existing Remote Desktop sessions may stop disconnecting or logging off cleanly once a server begins to fail, while new connection attempts stall and then time out. Readers also reported that their Terminal Servers started showing the same behavior after the September updates were applied.
One reader told BleepingComputer that every terminal server in their environment failed within a day, with sessions dropping and no new connections possible, leaving a hard reset as the only fix. A Windows admin reported that Remote Desktop Services ran fine at first but crashed after the first user logged out, blocking anyone else from signing in. Restarting the server did not help that admin, but uninstalling the September update did.
One administrator investigating Windows Server 2022 said on Reddit that the RDP service stops responding when users log out. That admin said debugging pointed to what appeared to be a deadlock between Remote Desktop and the Local Session Manager, with the service hanging at RDPSERVERBASE!WDLIB_Close and no timeout configured to break the stall. Microsoft has not confirmed that as the cause.
Rolling back the September updates restores Remote Desktop functionality for the admins who tried it, but it also removes the security fixes shipped in this month's Patch Tuesday release. BleepingComputer contacted Microsoft to ask whether the company is aware of the reported Remote Desktop Services problems and whether a fix or mitigation exists, and had not received a response at the time of publication. The site said it would update its article if Microsoft provides more information.
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