Windows 10 automatically restart the PC whenever it installed updates that required a mandatory reboot in order to finish installed. User can no longer delay or postpone a restart indefinitely. The best a user can do is to schedule a time for Windows to automatically reboot, or since Windows 10 Anniversary Update, set an active hours which Windows definitely won't restart the device. After installing updates that required a reboot to finish installing, Windows would normally ask user to restart. If the user does not restart the OS after a certain period of time, Windows 10 may start to show warning that operating system is going to restart at a specific time or after a certain duration of time. Eventually, Windows 10 will automatically restart, with or without user's consent. Theoretically, Windows would only restart the computer automatically when user is not using the computer, but it's not always the case. In fact, sometimes Windows 10 may wake up the computer to install the updates, and then auto-reboot. If you're not fond of surprise or unpredictable Windows restart due to Windows Update, or face the situation when updates take a long time to install during the reboot, there are several steps that you can take to avoid automatic restart after installing updates.
The following tutorials will guide you on how to prevent and stop Windows 10 from automatic restarting after updates are installed, permanently.