[German]The cumulative security updates released for Windows on April 14, 2024, are causing some issues. I have received several user reports indicating that users are unable to log in after installing the April 2026 updates. This affects Windows Server, but likely also Windows 11 clients (though that may be a different issue).
Windows Updates April 2026
On April 14, 2026, Microsoft released cumulative security updates for the Windows client and Windows Server versions that are still supported. I covered this in the blog post Patchday: Windows 10/11 Updates (14. April 2026) as well as in the post Patchday: Windows Server-Updates (14. April 2026).
Reports of Login Issues
But there is another problem that prevents users from logging in. And it's not an isolated case. On April 17, 2026, German blog reader Toni K. contacted me via email and reported login issues under the subject line "Windows Server 2025 DC Issues After KB5082063." He stated that "in the days following the installation of KB5082063, that he had encountered issues on Server 2025 DCE as an AD domain controller."
I also got reports on login issues at Windows 11 24H2 and 25H2 clients. Details may be read within my Geman blog post Windows April 2026-Updates verursachen Anmelde-Probleme [use build-in translator to switch language].
