Hi Viacheslav, This is Ramesh.
There is no built-in option to permanently turn off Windows Update, but there are other methods to accomplish the task.
There is third-party software named StopUpdates10 that aggressively disables Windows Update by disabling the service and setting a debugger value in the registry so that Windows Update and feature updates can't run. Even if you or the OS enables it, StopUpdates10 monitors the Windows Update service and turns it off automatically.
(or)
Create a System Restore Point. Open Regedit.exe. In the Registry Editor, go to:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\UsoSvc
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DoSvc
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Wuauserv
In each of the above keys, set the "Start" value to "4".
Restart Windows.
Important:
Disabling Windows Update has some disadvantages and risks.
Microsoft Store can't install or update apps.
Any software that relies on Windows Updates or BITS will fail to update correctly.
Your system will be vulnerable if it's not updated. Disable Windows Update at your own risk.
When you want to install updates, you can click "Restore Windows Updates" in the StopUpdates10 app and install them during nonproductive hours. This is a better option to ensure your system is not vulnerable.