How to Get Your Admin Password in Mac if You Don't Know Itby Jedadiah Casey
Apple computers running the Mac OS X operating system allow for the creation of two different kinds of primary user accounts -- administrator and standard. A standard account has limited permissions and requires the password of an administrator account before it is able to make changes to the computer. Without the administrator password, important system changes cannot be made. You can get a new administrator password on the Mac if it is lost or forgotten through single user mode.
Power on or restart the computer, and then immediately press and hold "Command" and "S" until a black screen appears.
Type "mount -uw /" without quotes, and then press "Return."
Type "launchctl load /System/Library/LaunchDaemons/com.apple.DirectoryServices.plist" without quotes, and then press "Return."
Type "ls /Users" without quotes, and then press "Return." This displays the list of user accounts on the system.
Type "dscl . -passwd /Users/account password" without quotes, and then press "Return." Replace "account" with the account needing the administrator password. Replace "password" with the new administrator password.
Type "exit" and then press "Return" to reboot the computer.