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Microsoft Issues Emergency Patch After September Update Breaks Remote Desktop

Emergency out-of-band updates restore Remote Desktop and repair some Hyper‑V and USB audio functions, with other regressions still under investigation

Overview

  • A large Patch Tuesday release on Sept. 8 delivered hundreds of security fixes but caused Remote Desktop Services to become unstable on Windows Server, Windows 10 and Windows 11 devices, preventing new RDP sessions and hanging some servers.
  • Microsoft published temporary Group Policy mitigations and advised stopping and restarting affected virtual machines as short-term workarounds while engineers investigated the failures.
  • On Sept. 14 Microsoft pushed multiple mandatory out-of-band cumulative updates (example KB5129194, KB5129195, KB5129236 and others) that restore RDS, fix Hyper‑V Plan9 host‑folder share problems and repair some USB Audio Class 1.0 multichannel issues.
  • Administrators are urged to install the OOB updates via Windows Update, WSUS or the Microsoft Update Catalog because rolling back the Sept. 8 patches restores functionality but also removes the month’s security fixes.
  • Some reported regressions remain unresolved, including Explorer.exe crashes, File History detection failures and certain AMD GPU and USB audio faults, and Microsoft says it is still investigating those ongoing issues.