Read the detailed section of this article for step-by-step instructions on regaining access to your root account. Here are the steps to retrieve access to root: 1. Click Restart at the login window 2. While the computer is restarting, hold down “Command-S” until you see text scrolling through the window. This boots the computer into single user mode. 3. At the Localhost% prompt type: /sbin/mount -uw / /sbin/SystemStarter You will then see various services starting up. 4. When the Localhost% prompt reappears, type: passwd root It will then ask you to type the new root password twice, so do so. 5. After entering the new password, type: reboot At the login window, enter username root wih the new password. Once you are connected, you can use the Multiple Users application (/Applications/Utilities) to change your normal user’s password, or create a new user account. Source: http://www.macpassword.com/recovering-lost-mac-root-password.html
Root user is special user in Mac OS X, has high privileges and rights to make any type of change to the system, and is different than administrator. If you forgot root password, see how to reset Root user password using different methods in Mac OS X. How to Reset Root User Password on Mac OS X
