Windows 11 Security Update Causes Domain Trust Failures and Service Regressions

Microsoft’s Windows 11 security update KB5124008, covering versions 24H2 and 25H2 with OS builds 26100.9445 and 26200.9445, introduced security improvements and Secure Boot certificate deployment but also caused operational regressions. Microsoft reported domain trust failures associated with Machine Identity Isolation enforcement, alongside problems affecting remote desktop services, virtual-machine folder sharing, backups, and desktop loading. Subsequent updates address most listed issues; a separate USB audio regression remains only partially resolved. The notice identifies no specific CVEs, active exploitation, or security breaches.

Microsoft also states that Windows 11 24H2 Home and Pro support ended on October 13, 2026, making migration to a supported release a priority for affected deployments. Administrators should review the documented fixes and deployment requirements intended to prevent installation-media boot failures. Separately, Microsoft updated its release history for locally running Windows AI components on Copilot+ PCs, including Execution Provider, Phi Silica, and image and semantic-processing components. That history lists releases through September 22, 2026, but does not establish that the AI component updates address security vulnerabilities or are connected to the reported regressions.