What is the Keychain?
The keychain in Mac OS X is Apple’s password management system.
A keychain can store all your passwords for applications, servers, and websites, or even sensitive information unrelated to your computer, such as credit card numbers or personal identification numbers (PINs) for bank accounts.
When you connect to a network server, open an email account, or access any password-protected item that is keychain-aware, your keychain can provide the password so you don't have to type it.
You start with a single keychain, which is created automatically the first time you log in to your Mac OS X user account. Your default keychain has the same password as your login password. This keychain is unlocked automatically when you log in to Mac OS X and is referred to in Keychain Access menus as the "login" keychain.
Keychain problems occur when a user's login password does not match their keychain password. This can be caused by using authentication methods other than the standard OS X local account system, like updating the user password through the YKSD Self Service portal. When the password used to log into the machine does not match the current keychain password, the keychain does not unlock for use with password management. The user is able to log onto the machine, but applications that use the keychain system, such as Safari or Mail, will give the user an error message stating that the application wants to use the "login" keychain. It will ask for the keychain password.
These dialog boxes will continue to pop up until the keychain has been fixed.
Changing Your Keychain Password
When a keychain mismatch occurs, the user must change their keychain password to match the password used to log on to the machine. To correctly change your keychain password, the user will use the application Keychain Access. Keychain Access is located in Applications\Utilities. It should look like this:
To change your keychain password:
If you do not remember your old password, you will need to manually delete and recreate your keychain.