Windows Server Patch Tuesday Causes Remote Desktop Outages Across Multiple Versions
Administrators report that the September 2026 cumulative updates for Windows Server 2019, 2022, and 2025 are causing Remote Desktop Services to fail after a few hours of normal operation. Symptoms include dropped sessions, inability to establish new connections, and in some cases requiring a hard reset to restore service. Rolling back the updates appears to resolve the issue, though Microsoft has not yet confirmed the root cause.
The reported failures specifically affect Windows Server 2019 (KB5122876), 2022 (KB5122882), and 2025 (KB5122871). One administrator's debugging pointed to a deadlock between Remote Desktop and the Local Session Manager, with a hang occurring in the RDPSERVERBASE!WDLIB_Close function that lacks a timeout.
While restarting the server does not fix the issue, administrators have found that uninstalling the September cumulative update restores normal Remote Desktop operations. However, this rollback also strips away the security fixes delivered in this month's Patch Tuesday. Microsoft has not yet acknowledged the problem or offered an official mitigation.
This disruption could significantly impact organizations that depend on Windows Server for remote workforce access. Businesses may face sudden productivity halts as employees lose the ability to connect to critical applications. IT teams could be forced to choose between maintaining operational uptime by rolling back patches or leaving systems exposed to unpatched vulnerabilities. This dilemma may also undermine confidence in automated patch management cycles, potentially leading to more cautious, manual update procedures across enterprise environments.