Apr 17, 2026 • Sergiu Gatlan
Microsoft: Some Windows servers enter reboot loops after April patches
Microsoft has identified a critical issue where Windows domain controllers are entering restart loops following the installation of April 2026 security...
Executive Summary
Microsoft has identified a critical issue where Windows domain controllers are entering restart loops following the installation of April 2026 security updates. This patch-related bug impacts critical infrastructure by rendering domain controllers unavailable, potentially disrupting Active Directory authentication and enterprise network operations. Organizations should immediately test patches in isolated environments before broad deployment and consider delaying the April 2026 update rollout on domain controllers until Microsoft releases a fix or workaround. Affected systems experiencing reboot loops may require manual intervention to restore functionality, representing a significant operational impact for enterprises relying on these systems for authentication and policy management.
Summary
Microsoft warns that some Windows domain controllers are entering restart loops after installing the April 2026 security updates. [...]
Published Analysis
Microsoft has identified a critical issue where Windows domain controllers are entering restart loops following the installation of April 2026 security updates. This patch-related bug impacts critical infrastructure by rendering domain controllers unavailable, potentially disrupting Active Directory authentication and enterprise network operations. Organizations should immediately test patches in isolated environments before broad deployment and consider delaying the April 2026 update rollout on domain controllers until Microsoft releases a fix or workaround. Affected systems experiencing reboot loops may require manual intervention to restore functionality, representing a significant operational impact for enterprises relying on these systems for authentication and policy management. Microsoft warns that some Windows domain controllers are entering restart loops after installing the April 2026 security updates. [...] Microsoft warns that some Windows domain controllers are entering restart loops after installing the April 2026 security updates. [...]