macOS Sierra: How do you enable shutdown keyboard shortcut (Ctrl + Opt + Cmd + Power)? After upgrading to macOS Sierra yesterday, I notice that the system keyboard shortcut to shut down the computer no longer works.

As documented here, before the upgrade you could shut down the computer using Control–Option–Command–(Power button or Media Eject).

After the upgrade, the system seems to ignore the "Control–Option–Command" combo and merely sleep the display as if I had tapped the Power button alone.

Do you know of any documentation on how to restore the old shortcut?
Ctrl + Cmd + Opt + Power/Eject still works in macOS Sierra. I just tested it with an upgraded install (El Capitan to Sierra) on an MBP Mid-2014. Please see if another keyboard shortcuts overrides the shutdown command:

System Preferences > Keyboard > Shortcuts

After upgrading to macOS Sierra my keyboard shortcut for Spotlight (CMD + Space) was changed to Ctrl + Space. I had to change it manually to restore the functionality.

Edit:
John, please do the following: Backup all PLIST-files starting with com.apple. + pbs.plist + ".GlobalPreferences.plist (in Terminal:

cp -f ~/Library/Preferences/.GlobalPreferences.plist ~/Desktop
# this will copy the file as a backup to the Desktop

rm -f ~/Library/Preferences/.GlobalPreferences.plist
# this will delete the original file


Also backup the folder ~/Library/Caches/. Now delete everything inside this folder. Empty the trash and reboot.