OS X Lion: Apple ID can be used to reset your user account password

What's an Apple ID?

An Apple ID lets you personalize your Apple experience. You use your Apple ID to access Apple resources that require you to identify yourself. Learn more about your Apple ID.

How to allow your Apple ID to reset your OS X Lion user password

When you start OS X Lion or a new Mac with Lion for the first time, you enter the Mac OS X Setup Assistant. You will be asked to "Enter Your Apple ID". After entering your Apple ID, select the "Allow my Apple ID to reset this user password" option. during the "Create your Computer Account" stage.

If you didn't enter your Apple ID during the Mac OS X Setup Assistant or your Mac already has its user accounts, you can follow these steps:

1. Open System Preferences, then click Users & Groups.
2. To bind an Apple ID to your OS X Lion user account, click the Apple ID: "Set…" button and enter a Apple ID name and password, or click the "Create Apple ID…" to create a new Apple ID using Safari.
3. Select the "Allow user to reset password using Apple ID" check box.

Note: FileVault 2-enabled Macs will not show a "Allow user to reset password using Apple ID". Learn more about FileVault 2, including how to reset its password.
 

To reset your OS X Lion user password with your Apple ID

If you incorrectly enter your account password at the login window three times, a message appears stating "If you forgot your password, you can reset it using your Apple ID".  Click the arrow-in-a-circle icon to bring up the "Reset Password" dialog. Enter your Apple ID and password, then click "Reset Password" to proceed.

Note: In some cases, you may not be presented with the opportunity to reset the password after three incorrect attempts. If this happens, open Users & Groups preferences, remove the affected Apple ID, and then add the same Apple ID back. This issue could occur after upgrading from Mac OS X v10.6.

Note: Changing the user account password will create a new keychain. The previous keychain still exists and can be accessed if you later remember the previous password.

Click "OK" in the dialog that appears to inform you about the new keychain.

Enter a New password, Verify password and Password hint fields, then click "Reset Password" to proceed.

Click "Continue Log In" to finish logging in using the new password you just created.