MICROSOFT released an out-of-band update on 14 September 2026 to address problems introduced by its 8 September Patch Tuesday release, which contained fixes for 974 CVEs. The issues affected some environments using Remote Desktop Services (RDS), where connections could fail after several minutes, sign-ins could be blocked, or servers could hang at “Please wait for the Remote Desktop Configuration”. Microsoft also reported that Microsoft Management Console, RDS Licensing Diagnoser, File Explorer and the Windows Update page could become unresponsive.
The update, KB5129195, also resolves problems for Hyper-V users running Claude Cowork, Windows Subsystem for Linux (WSL) and other applications. Virtual machines could start normally while host folders shared through Plan9 were unavailable inside the guest, causing dependent applications or sandbox environments to report that no Plan9 drive shares were mounted. In addition, some USB Audio Class 1.0 devices could fail to start or produce no audio after the original security update.
Microsoft said administrators who applied a temporary Group Policy mitigation do not need to remove it before installing KB5129195, which is cumulative and includes earlier Windows improvements and security protections. The company described this as the sixth emergency patch issued to address failures linked to September’s Patch Tuesday.