Norton had been showing a patch available for some time. When I installed by restart it seemed to apply, but when I did a security update, it still said a patch was available.
Today, when I selected the option to apply the patch now, the process started (displayed the message at the top), but - to my surprise and dismay - the screen shifted to the screen that is displayed when Windows is doing an update of Windows itself - the "configuring windows do not turn off your computer". In other words, the NIS patch was doing something that Windows saw as changing the O/S itself at a fundamental level!
So of course I shut down the computer. When I restarted, Windows fortunately displayed the message that the update had failed and the attempted changes had been rolled back. Windows then started normally.
I've used Norton for a long time (back to when it was really 'Norton Utilities').
No more. For a program to have a faulty patch that tries to fundamentally change the O/S itself is a program that shouldn't be used.