Microsoft Fixes September Update Breaking RDP and Linux VMs

Microsoft issued out-of-band updates on 14 September 2026 to address several problems linked to its record-setting September Patch Tuesday release. The update addressed 974 unique CVEs, compared with 909 CVEs patched during all of 2023. Microsoft said some organisations experienced instability in Remote Desktop Services (RDS), including failed RDP connections after several minutes, sign-in problems and servers becoming stuck at “Please wait for the Remote Desktop Configuration”.

Microsoft Management Console, RDS Licensing Diagnoser and File Explorer could also become unresponsive, while the Windows Update page could remain stuck loading.

The September update also affected some Hyper-V-based Linux virtual machines, where host folder shares became unavailable, and some USB audio devices operating in multichannel mode, which failed to start or produced no sound. The report does not say that these issues were security exploitation; they were unintended effects of the update. Security specialists quoted by Dark Reading said the incident showed the operational risks of increasingly large and complex patches.

They recommended risk-based deployment using staged rollout rings, representative testing, rollback capability and enhanced monitoring, while noting that delaying security updates can leave organisations exposed to active exploitation. Microsoft’s emergency fixes should therefore be assessed and deployed by affected organisations, with testing before broad installation where operationally possible.