I needed to do some file moving between users and noticed my admin account didn’t have access, so I tried “su” and “sudo” without success. Apparently, like it Yosemite, root access is disabled by default. Here’s how to enable it:
1. Open Directory Utility (I usually do it via CMD + spacebar, then type "dire")
2. Go to the Edit menu and select "Enable Root User".
3. Enter your desired root password twice.
4. That's it!
Test it out in the terminal by doing:
$ su -
Happy rooting, yo!