Occasionally users will encounter password issues that Keychain Access cannot repair using Keychain First Aid. In these cases, users can reset their keychain. Resetting your keychain can also help if you cannot remember your original keychain password. Keep in mind that resetting your keychain archives your original passwords and starts a new keychain.
To reset your keychain, follow these instructions (For Mac OS X 10.4 and greater):
Open Keychain Access (Applications > Utilities) and choose Preferences from the Keychain Access menu bar > Keychain Access (Command + ,).
From the General tab, click "Reset My Default Keychain" and authenticate with your account password.
Quit Keychain Access and restart your Mac.
Again, your original keychain will simply be set aside when you reset your default keychain in this manner. If you are having issues with your keychains and have not run Keychain First Aid, open Keychain Access and choose Keychain First Aid from the Keychain Access menu bar > Keychain Access. Enter your user name and password and click Start. Repair any problems that Keychain Access finds and you should be good to go.