After you change your password, you will need to create a new keychain for the new password on the Mac side.
Respond to the Keychain Error Message
After you enter your password to log on to your computer for the first time after changing your password, you will be prompted with a Keychain Error that says "The system was unable to unlock your login keychain."
If this does not work...
If updating your keychain does not work, you may need to delete your keychain and create a new one. Make sure that you have memorized all of your passwords before deleting the keychain.