How to disable Windows 11 automatic reboots?

Try the Dan Oross solution.

_______________

1. Open Notepadand enter these four lines of text...

for /f "tokens=*" %%a in ('powershell "(Get-Date).Hour"') do set startHour=%%a

set /a "endHour=(%starthour%+18)%%24"

reg add HKLM\SOFTWARE\Microsoft\WindowsUpdate\UX\Settings /v ActiveHoursStart /t REG_DWORD /d %startHour% /f

reg add HKLM\SOFTWARE\Microsoft\WindowsUpdate\UX\Settings /v ActiveHoursEnd /t REG_DWORD /d %endHour% /f

2. Save the file as "Roll_Active_Hours.cmd". Don't use .BAT. It's ancient DOS. .CMD is slightly more modern, the NT era.
3. Open Task Scheduler and create a new task. Select "Run with highest privileges" and "Run whether user is logged in or not" and "Configure For: Windows 10", since there is no Windows 11 option within Windows 11.
4. In Triggers, create a single trigger. Choose "One time" and choose today's date and 12:00:00 PM. Then select Repeat task every: 12 hours. If there is no option in the drop down for 12 hours... just type it in. I check "Stop task if runs longer than: " and select 1 minute. If it takes longer than that, something is wrong. And of course, check the Enabled box to activate the trigger.
5. In the Actionstab, select "Start a program" and then use the Browse... button to locate the "Roll_Active_Hours.cmd" script from steps 1 and 2.
6. Everything on the Conditionstab should be unselected. In the Settingstab, check "Allow task to be run on demand" and "Run task as soon as possible after a scheduled start is missed" and "If the running ask does not end when requests, force it to stop".

That's it. No windows flashing when the task runs. Only runs twice per day. You can run it manually if you like. And Windows 11 will never restart on its own.

___________

This still the best solution for this problem.

However, it's recommend check if there's a update needing to restart.

I spend days without checking and the update does not force restart.

My simple solution for this for the last couple of years of using Win11 on a fileserver at home has been to use "Pause updates". I choose "Pause for 5 Weeks" and try to schedule a manual Check for update, update and reboot once a month, but of course if i don't remember.. the server reboots itself after 5 Weeks ;-)

I also use this "Pause updates" on my media PC connected to the Home Cinema, hate updates during watching films and series..

Will try this "Active hour" trick to see if that works.

Arild

Why is forced rebooting a thing at all? The reason I use Microsoft as opposed to Apple WAS that I had control of the machine and I could customize it's operation to fit me and my work. Forcibly taking control of the machine like this and giving us users no options to something as simple as keeping the machine on is not how an operating system should function. I know that Microsoft doesn't care AT ALL about user feedback and how people might want to use their software. So largely I'm just commiserating with the rest of you. There is no hope. Put that out of your mind. Microsoft will not listen or change. We must just adapt and fight with third party solutions and hacks to make our machines do basic tasks. So keep doing what you can and I appreciate everyone who posts their workarounds and solutions. Thank you to everyone who has these same problems and keeps posting. Makes me feel like I'm not the only one who enjoys a computer they can control.

You know, I've tried this and so many options to no success. And now yet again Microsoft reboots my computer for bloody updates in the middle of the night and work is lost from the previous day on my university paper.

This is exactly why I am about to switch platforms back to Apple

is there a way to find it again to even see if its added? i cant seems to do that, i also noticed most my issues start when it updated microsoft windows defender updates