Reset Keychain

You may have found yourself unable to get your computer to save your passwords. Mac OS X may prompt you to save your password to your "keychain", and then it turns right around and prompts for a password to unlock your keychain. Can't remember your keychain password?

Don't worry, resetting it is pretty easy.

Go to Applications, then Utilities, and then open Keychain Access.

When the program opens, go to the Keychain Access menu and click Preferences.

Under Preferences, click Reset My Keychain.

(From http://support.apple.com/kb/TS1544)