Information
In the GUI both 'Install macOS updates' and 'Install app updates from the App Store' are dependent on whether 'Download new updates when available' is selected
Rationale:
It is important that a system has the newest updates downloaded so that they can be applied.
Impact:
Without updates available they may not be made in a timely manner and the system will be exposed to additional risk.
Solution
Perform the following to enable the system to automatically check for updates:
Graphical Method:
Open System Preferences
Select Software Update
Select Advanced
Select Download new updates when available
Terminal Method:
Run the following command to enable auto update:
$ sudo defaults write /Library/Preferences/com.apple.SoftwareUpdate AutomaticDownload -bool true