Overview
Windows administrators are reporting widespread Remote Desktop Services (RDS) failures following the September 2026 Patch Tuesday cumulative updates. The issue affects Windows Server 2019, 2022, and 2025, preventing users from connecting and, in some cases, requiring hard resets to restore functionality.
Symptoms Reported
- Connection failures: RDS servers initially work but begin failing after a few hours.
- Session hangs: Existing sessions cannot disconnect or log off properly.
- New connections blocked: Attempts to connect hang and eventually fail.
- Deadlock suspicion: Debugging suggests a deadlock between Remote Desktop and the Local Session Manager, with no timeout set.
Affected Versions
- Windows Server 2019 — KB5122876
- Windows Server 2022 — KB5122882
- Windows Server 2025 — KB5122871
Admins report that rolling back the September updates restores RDS functionality, but this also removes critical security fixes included in the Patch Tuesday release.
Community Feedback
- Reddit admins: Multiple threads describe servers failing within a day of patching.
- Reader reports: Terminal servers dropping sessions and blocking new connections.
- Debugging insights: RDP service hangs at
RDPSERVERBASE!WDLIB_Close, causing deadlocks.
Defensive Guidance
Administrators should:
- Monitor Microsoft advisories for official fixes.
- Test updates in staging before deploying to production servers.
- Consider temporary rollback if RDS outages severely impact operations.
- Track logs for signs of deadlocks or service hangs.
- Apply mitigations once Microsoft provides interim guidance.
Expert in the Cloud Insight
This incident highlights the delicate balance between patching for security and maintaining service availability. While rolling back updates restores RDS, it exposes systems to unpatched vulnerabilities. The lesson is clear: organizations must weigh operational continuity against security risk, and closely monitor vendor advisories for rapid remediation guidance.
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