Keychain issue for Mac OS X

Laptop: MacBook Air 

Operation System: Mac OS X 10.4 or later

 Error Message: The system was unable to unlock your login keychain "alert after logging in". 

The quickest way to reset your keychain in Mac OS X 10.4 or later:

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

Solution: 

This occurs when a password has been changed without connected to a company VPN. If the computer have join a company domain and the password changed while not on VPN, the password sync between company domain controller and the MacBook will promote this message.

1. Open Keychain Access from Utilities folder within the Applications folder.
2. From Keychain Access > choose Preferences. 
3. Click General > Reset My Default Keychain. 
4. Authenticate with your account log in password. 
5. Exit Keychain Access 
6. Restart the MacBook and issue will be resolved.