Windows 11 25H2 forces automatic reboot during active hours when user is away – GPOs correctly set but ignored

Windows 11 25H2 is treating several of the classic Windows Update restart GPOs as legacy and effectively ignoring them in favor of the newer deadline-based behavior. To stop unexpected reboots during active hours when users are away but logged on, the configuration needs to be shifted from legacy restart policies to the newer deadline/compliance model and the recommended active-hours behavior.

Key points from the current configuration:

• Configure Automatic Updates = 4 (scheduled install) is still valid.
• No auto-restart with logged on users for scheduled automatic updates installations and Always automatically restart at the scheduled time and similar are legacy restart policies and are called out as not recommended for newer Windows versions.
• Turn off auto-restart for updates during active hours is valid, but on its own it does not override deadline/compliance behavior once deadlines/grace periods are reached.

On Windows 10/11, Microsoft recommends avoiding the legacy restart-delay policies and instead using the deadline policies, combined with active hours, to prevent restarts while users are working and still guarantee compliance.

Recommended configuration to prevent reboots while the user is away but logged on:

1. Stop using legacy restart-delay policies
   • Do not rely on:
     • Specify deadline before auto-restart for update installation
     • Delay Restart for scheduled installations
     • Other legacy restart GPOs listed as “policies not to set”.
   • These are explicitly documented as legacy and not applicable for Windows 11; they can have no effect or conflicting behavior.
2. Use the new deadline policy instead of legacy restart control
   • Configure the policy:
     • Computer Configuration > Administrative Templates > Windows Components > Windows Update > Specify deadlines for automatic updates and restarts
   • Set (for example, per Microsoft recommendation):
     • Quality update deadline (days): 7
     • Feature update deadline (days): 2
     • Grace period for quality updates (days): 2
     • Grace period for feature updates (days): 7
   • In the same policy, select:
     • Don’t auto-restart until end of grace period
   • This combination ensures:
     • Windows will look for a minimally disruptive time to restart.
     • Automatic restarts outside active hours are prevented until the deadline + grace period is reached.
     • Users get notifications and can choose when to restart, but the system will not force a restart during active hours until the deadline/grace period has passed.
3. Keep active hours configured, but let Windows manage restarts within that framework
   • Either:
     • Allow users to set their own active hours (recommended), or
     • Configure Turn off auto-restart for updates during active hours with an appropriate window (for example, 05:00–22:00 as currently used).
   • With the deadline policy and “Don’t auto-restart until end of grace period” enabled, Windows will:
     • Avoid automatic restarts during active hours until the deadline/grace period is exceeded.
     • After deadline+grace, restart can occur even during active hours to guarantee compliance.
4. Let Windows choose the least disruptive restart time
   • Ensure the MDM/registry equivalent of ConfigureDeadlineNoAutoReboot is not used to block Windows’ ability to pick a low-impact restart time.
   • Documentation explicitly recommends leaving ConfigureDeadlineNoAutoReboot disabled so Windows can use user activity signals to find a minimally disruptive restart time.
5. Keep Configure Automatic Updates = 4 if scheduled install is required
   • With AUOptions = 4 and the deadline policy in place, installation still happens on the scheduled basis, but restart behavior is governed by the deadline + grace period + active hours logic instead of the legacy restart timers.

Effect on the described scenario:

• During the day, updates install as before.
• A restart notification appears with options to restart or postpone.
• If the user is away when the notification appears, Windows will not immediately force a restart during active hours as long as the deadline and grace period have not expired and “Don’t auto-restart until end of grace period” is set.
• Restarts will be pushed to non-active hours or to a later time within the grace period, significantly reducing the risk of data loss from short absences.

If strict prevention of any forced restart during active hours is required even after deadlines, the only supported way is to adjust deadlines and grace periods so that forced restarts are likely to occur outside working hours (for example, shorter deadlines but with maintenance windows outside active hours), while accepting that once deadline+grace is passed, Windows may restart regardless of active hours.

References:

• Walkthrough: Use Group Policy to configure Windows Update client policies
• Manage device restarts after updates
• Avoid legacy policy configurations
• OS Updates
• Policies for update compliance, activity, and user experience