Microsoft says some Windows 11 devices cannot reliably connect to enterprise networks over Always On VPN after installing September 2026 security updates. The issue affects Windows 11 versions 24H2, 25H2, and 26H1 after KB5124008 or KB5124012, especially when the VPN profile is set to automatically switch between IKEv2 and SSTP if one protocol fails. Microsoft said affected systems may get stuck in a connecting loop or show a port-in-use error, and it recommends temporarily forcing a single tunneling protocol until a permanent fix is released.
Why it matters: Organizations that rely on Always On VPN for secure remote access may suddenly lose dependable connectivity after applying September updates. IT teams should review affected VPN profiles now and switch from automatic protocol selection to either SSTP-only or IKEv2-only while waiting for Microsoft's fix.
Sergiu Gatlan
2026.09.23
100% relevant
This article establishes a distinct Microsoft post-patch enterprise access problem centered on Always On VPN failures caused by specific September 2026 Windows updates.
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