How to Change Your Password in Mountain Lion

By Bob LeVitus from OS X Mountain Lion For Dummies

You can change your password on your Mac running OS X Mountain Lion at any time. Changing your password is a good idea if you’re concerned about security — for example, if there’s a chance your password has been discovered by someone else.

You can change the password for your account on your own Mac, or you can change the password you use to connect to your account on a remote Mac.

Change your account password on your Mac

To change the password on your own Mac, just follow these steps:

Choose Apple→System Preferences, or double-click its icon in your Applications folder and click the Users & Groups icon.

The Users & Groups System Preferences pane appears.
Select your account in the list on the left.

Your account information appears in the area on the right.
Click the Change Password button.

A sheet drops down.
Type your current password in the Old Password field.

This demonstrates that you are who you’re supposed to be, not someone who just walked up to your unattended Mac.
Type your new password in the New Password field.
Retype your new password in the Verify field.
(Optional but recommended) Type a hint in the Password hint field.
Click the Change Password button.

Assuming that you entered your old password correctly, the sheet disappears.
Close the System Preferences window.

Change the password of any account but your own

To change a password on your own Mac, just follow these steps:

Choose Apple→System Preferences, or double-click its icon in your Applications folder and click the Users & Groups icon.

The Users & Groups System Preferences pane appears.

You may have to click the lock (at bottom left), supply an administrator name and password in the resulting dialog, and then click OK before you can proceed.
Select the account you want to change the password for in the list on the left.

The account information appears in the area on the right.
Click the Reset Password button.

A sheet drops down.
Type the new password in the New Password field.
Retype the new password in the Verify field.
(Optional but recommended) Type a hint in the Password Hint field.
Click the Reset Password button.
Close the System Preferences window.

Change your password on someone else’s Mac

When you log in to a remote Mac, you can change your own password if you like. Follow these steps to do so:

Log in to the remote computer on which you want to change your password.

The Connect dialog appears.
Type your username in the Connect dialog, if it’s not already there.
Click the Change Password button in the bottom-left corner of the dialog.

A sheet for changing your password appears.
Type your current password in the Old Password field.
Type your new password in the New Password and Verify fields.

You can use the Password Assistant (the little key to the right of the New Password text box) to help you generate a secure password.
Click the Change Password button.

Your password is changed, and you return to the Connect dialog.
(Optional) Type your new password and click Connect to log in to the other Mac.

You can skip this step by clicking the Cancel button in the Connect dialog if you don’t need to use anything on the remote Mac at this time. Your password is still changed, and you need to use the new password the next time you log in to this Mac.

Select the Add Password to Keychain check box in the Connect dialog to store your passwords in a single place on the Mac; this way you don’t have to retype them each time you access a Mac or other remote resource.