September 2026 Windows 11 Updates Cause Always On VPN Connectivity Issues

Microsoft has warned IT administrators that the September 2026 Windows 11 security updates may cause Always On VPN connectivity problems on affected devices.

Always On VPN connections may remain stuck

Always On VPN is a remote access solution that replaces traditional DirectAccess technology. It works with domain-joined, non-domain-joined, and Microsoft Entra ID-joined devices.

Available on Windows 10, Windows 11, and Windows Server, Always On VPN runs in the background and automatically establishes a secure tunnel to an organization’s corporate network whenever a device connects to the internet.

Administrators can also define which apps and services use the VPN connection. The technology supports modern VPN protocols, including IKEv2 and SSTP, as well as multi-factor authentication (MFA).

According to a Microsoft service alert seen by BleepingComputer and shared by Microsoft MVP Susan Bradley, affected customers may experience problems when their systems attempt to connect to their organization’s enterprise network through Always On VPN.

Microsoft says the issue can occur when a VPN is configured to automatically try an alternative connection method if the first connection fails. This includes configurations that use automatic protocol selection with IKEv2 or SSTP.

"Affected VPN connections may remain in a ‘connecting’ state or may not succeed after repeated attempts to connect," Microsoft said. "Subsequent connection attempts may also result in a ‘The specified port is already in use’ error."

Windows 11 versions affected by the VPN issue

Microsoft shares temporary Always On VPN workaround

Microsoft is still working on a permanent solution. In the meantime, it recommends that affected organizations change their Always On VPN profile from automatic protocol selection to a single VPN tunneling protocol.

"IT administrators can alleviate this issue by changing the Always On VPN profile from automatic protocol selection to a single protocol of SSTP only or IKEv2 only, depending on the environment and configuration," Microsoft said.

Organizations should choose between SSTP and IKEv2 based on their environment, security requirements, and deployment configuration.

Other problems linked to the September 2026 updates

The September 2026 cumulative updates are also associated with multiple other issues affecting home and business Windows users.

A week ago, Microsoft released an emergency update to fix the issue. Hyper-V issues, Remote Desktop Services failures, and USB audio problems are also caused by the September 2026 update.

Microsoft also shared a temporary workaround for an issue that prevented some Windows 11 users from logging in with valid domain credentials. The company is additionally working to address a bug that could cause Windows’ built-in File History backup feature to stop working.

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