Mac Reset Password Single User

Change Password in Mac OS X Single User Mode

Enter Single User Mode. Reboot the Mac and hold down Command+S at boot to enter into the command line. Run two commands in order to make filesystem changes. The first command checks the Mac OS X filesystem for errors and fixes them.

fsck -fy

The next command mounts the root Mac OS X drive as writable, allowing you to make changes to the filesystem:

mount -uw /

After the filesystem is mounted, you can reset any users password using the following command:

passwd username

To reset your keychain in Mac OS X 10.4, Mac OS X 10.5, and Mac OS X 10.6 Snow Leopard or later

Open Keychain Access, which is in the Utilities folder within the Applications folder.
From the Keychain Access menu, choose Preferences.
Click General, then click Reset My Default Keychain.
Authenticate with your account login password.
Quit Keychain Access.
Restart your computer.

To reset your keychain in Mac OS X 10.3 through 10.3.9:

Open Keychain Access, which is in the Utilities folder within the Applications folder.
From the Window menu, choose Keychain First Aid.
Click Options...
Click Reset My Keychain, which is under the General pane.
Authenticate with your account login password.
Quit Keychain Access.
Restart your computer.