Microsoft September Updates Disrupt Always on VPN Links
Security patches for Windows 11 cause persistent connection errors for corporate users relying on automatic protocol selection.
Key points
- September 2026 Windows 11 updates break Always On VPN when automatic protocol selection is enabled.
- Microsoft advises IT admins to manually set the VPN to use only SSTP or only IKEv2.
- The same updates caused separate issues with Hyper-V, Remote Desktop, and USB audio.
Microsoft warned IT administrators that September 2026 security updates may break Always On VPN connections. This affects specific Windows 11 versions where the system attempts to connect to corporate networks automatically.
The issue causes connections to stall in a 'Connecting' state or fail repeatedly. Users may see an error stating that a specific port is already in use. BleepingComputer reported on the service alert shared by Microsoft.
Automatic protocol selection causes failures
Always On VPN replaces older remote access tools. It creates a secure tunnel to company networks in the background. The system supports modern protocols like IKEv2 and SSTP for better security.
The problem arises when the VPN is set to automatic protocol selection. If the first connection method fails, the system tries another. This switch can trigger the connection errors described in the alert.
Temporary fix requires manual protocol choice
Microsoft has not yet released a permanent solution. IT managers must apply a temporary workaround to restore service. They need to change the VPN profile settings on affected devices.
Administrators should disable automatic protocol selection. They must choose either SSTP or IKEv2 exclusively. The choice depends on the organization's specific security and deployment needs.
Other Windows issues persist this month
These updates have caused multiple other problems for users. Microsoft recently released emergency patches for Hyper-V and Remote Desktop Services. USB audio issues were also linked to these changes.
Some users face login blocks with valid domain credentials. A separate bug may stop the File History backup feature from working. Microsoft is working to address these remaining issues.
