Apple instructions are missing a step: they do not instruct the user to "Login Options" in the Users & Groups Menu, where Network Account Server lives, and the "Join...." button is located.
I received an Adobe Acrobat update this morning, and tried to install it.
Towards the end of the process, I received an error alert (1013).
Checking with Adobe, their recommendation was to enable the root user to complete the installation.
Checking with Apple, there were three different articles about enabling the root user, and each one of their instructions referred to
"Add" or "Edit" buttons in the System Preferences/Users and Groups/Login Items.
There are no such buttons or menus in the Login Items window.
Apple's instructions refer to items that don't exist in the Login Items window.
How do I enable the root user?