- 1). Click on the "Finder" icon in the dock to open a new Finder window.
- 2). Highlight "Applications" on the left side of the window and then open the "Utilities" folder.
- 3). Double-click on the icon labeled "Terminal."
- 4). Type "sudo --s" (without quotes) into the blank command prompt window and hit the "return" key. You will now be prompted to log in with your computer's root password.
- 5). Enter the administrator password that you chose when you originally set up your MacBook, then press "return" to log in as the root user.
- 6). Type "sudo visudo" (without quotes) into the command prompt window and press "return."
- 7). Place your text cursor at the end of the line that contains the text "root ALL=(ALL) ALL."
- 8). Hit "return" to add a new line and then type "username ALL=(ALL) ALL" (without quotes). Replace "username" with the short name of the account you want to add to the sudoers list.
- 9). Go to "File" in the top menubar and choose "Save" to confirm the changes.
Source...