September Windows Server Updates Break Remote Desktop Services

System administrators are reporting widespread issues with Remote Desktop Services (RDS) after applying this month’s Windows Server cumulative updates. According to reports on Reddit and feedback shared with BleepingComputer, affected servers initially work normally before connections begin to fail. Existing Remote Desktop sessions may become unable to disconnect or log off, and new connection attempts can hang and eventually time out.

“All terminal servers in our environment are failing (sessions dropping, no new connections possible, only solution is a hard reset) within a day,” one system administrator told BleepingComputer. Another admin said the problem emerges after the first user logs out: “It works initially, but after the first log out, services crash and no further users can sign in.”

Rolling back the September update resolves the issue for those affected. One administrator investigating Server 2022 reported on Reddit that the Remote Desktop Protocol service becomes unresponsive when users begin logging out, with debugging suggesting a deadlock between Remote Desktop and the Local Session Manager. Microsoft has not confirmed this as the cause.

The failures affect Windows Server 2019, 2022, and 2025. Administrators who have not yet installed the September updates may wish to delay deployment until Microsoft provides a fix or workaround.

Why This Matters

Remote Desktop Services is a critical tool for IT teams managing servers remotely; disruptions can halt administrative workflows and impact business continuity.
The issue forces affected administrators to either roll back security updates or hard-reset servers, undermining the intended patch-and-protect cycle.
Temporary downtime or workarounds increase operational risk, especially for organisations relying on terminal servers for remote work or application delivery.

Background

The September 2026 Patch Tuesday addressed 966 vulnerabilities, including two zero-days. Such large cumulative updates can occasionally introduce regressions. Microsoft has a history of Patch Tuesday updates causing unintended side effects, such as print spooler or networking issues, but Remote Desktop failures of this scale have been rare in recent years.

Key Perspectives

Affected IT Administrators: Need a prompt fix from Microsoft; some may choose to defer the September update despite the security risk. Rolling back is the only reliable workaround reported so far. Microsoft: Has not publicly acknowledged the problem or provided a timeline for a resolution. The company typically investigates reported issues and may release an out-of-band fix or include a remedy in the next cumulative update. Security-Conscious Organisations: Face a dilemma between patching critical vulnerabilities and avoiding potential operational disruption caused by the RDS failure.

What to Watch

Microsoft’s response — an acknowledged issue in its Known Issues list or a hotfix would signal progress.
Community forums for additional workarounds or confirmation that the deadlock theory matches official engineering analysis.
Whether the problem extends to Windows Server 2022 RDS role or any other Windows versions beyond those already reported.

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