If you
disable 'Install Updates and Shut Down', it will not appear as a choice in the
Shut Down Windows dialog box and
Start Menu power button (alert shield on Shut Down button), even if important or critical Windows Updates are available for installation.
If you
enable 'Install Updates and Shut Down', it will override and display as the default option in the
Shut Down Windows dialog box and
Start Menu power button (alert shield on Shut Down button) when important or critical Windows Updates are available.