Q: Mac mini won't restart during app update

Checked into the App Store and there is an update for Safari, that requires a restart during installation.  So I click on Update.  The app starts to download and the window pops up stating the the system will restart in x number of seconds, with the option to "restart now".  So I clicked "restart now".  The restart procedure begins but stops and doesn't complete the restart, freezing the system, causing me to power the system off and reboot.

The same thing is happening when I try a normal shut down or restart from the Apple Menu or by pressing <Ctrl><Opt><Cmd> and the eject key.  The shut down process begins but never completes leaving the bottom menu bar and the display on.