Problem Description:
After upgrading most of our PCs from Windows 10 (versions 1607–22H2) to Windows 11 version 25H2, we are experiencing a critical issue related to system shutdown and restart.
Whenever a shutdown or reboot is initiated, the system gets stuck on the Windows shutting down / restarting screen indefinitely. Even after waiting more than 24 hours, the process does not complete. The only way to recover is to perform a forced power-off (cold start by holding the power button). After that, Windows starts normally.
This behavior occurs every time the system is shut down or restarted.
Troubleshooting already performed:
Clean installation of Windows 11 25H2 on brand-new hardware (no third-party software installed)
Installation of all available latest cumulative updates and patches
Testing across multiple devices and different hardware configurations
The issue also occurs on fresh installations, indicating that it is not related to third-party software or specific hardware.
Currently, over 100 PCs in our company are affected, causing significant operational disruption.
We would appreciate assistance in identifying the root cause of this issue and information on whether this is a known problem, including any recommended fixes or workarounds.

