How to create a root user on OS X:

To create a root user, go to:

Applications --> Utilities --> NetInfo Manager

NetInfo Manager

Launch NetInfo Manager, then select:

Domain menu --> Security --> Authenticate...

NetInfo Manager - Authenticate

Enter your Admin Username and Password, then click OK.

Unix Admin Username and Password

Choose:

Domain menu --> Security --> Enable Root User...

You will get an error dialog:

NetInfo Error

Click OK. You will then get a dialog box to enter a root user password. At the prompt enter your desired password, then confirm it.

Root Password

For security reasons, it is advisable that your root password be a different password than ones used for other purposes, such as standard OS X admin users or email accounts. Quit Net Info manager.