Microsoft fixes Always On VPN issues caused by September Windows updates

Microsoft released cumulative updates KB5127648 and KB5127646 to fix Always On VPN failures triggered by the September 2026 Windows 11 security updates on version 24H2 and later. Affected connections could hang in a Connecting state or fail with a "port already in use" error when automatic protocol selection was enabled.

• Updates KB5127648 and KB5127646 fix the Always On VPN bug
• Issue hit Windows 11 24H2 and later with automatic protocol selection
• Workaround: set the VPN profile to SSTP only or IKEv2 only
• September patches also broke Remote Desktop, Hyper-V and USB audio