How to reset Keychain password
1.  Click on Finder > Go > Utilities > Keychain Access. The Keychain Access window displays.
2.  From the Keychain Access menu, select Preferences. key3The Preferences window displays.key4
3.  Click Reset My Default Keychain.  This removes the login Keychain password and prompts you to create a new one.
4. In the Password field, enter your Active Directory (AD) password (what you log into the computer with).  This syncs the Keychain password to your current login password.
5.  If desired, click the checkbox to enable Show Password.
6. Click OK.  A window displays stating your Old Keychain password has been renamed.
7. Click OK.
If Reset My Default Keychain is not available, click Edit > Keychain List > Click Show > Ensure “user” is selected > Click to select the Login Keychain > Click the Minus sign (-) button to delete > The next time you log into your Macintosh, be sure to click the checkbox to Remember this password in my keychain.