Depending on your classification, you have to change your career account password every one, three or six months. When you do this outside of OS X (i.e. not using OS X's Users & Groups system preference), your OS X login keychain will become out of sync with your career account. For example, it's Friday afternoon, you change your career account password and then logoff and leave for the weekend. Monday morning, you arrive back to work, login to your Mac with your new password, but then quickly are greeted with a dialog box like so -
If you remember your previous password, you should press the 'Update Keychain Password' button. You'll then be prompted to enter your previous password. Once you've entered your previous password, your login keychain will be changed to your NEW career account password. Subsequent logins will not complain about the login keychain problem, until you change your career account password the next time.
If you do NOT remember your previous password, you should press the 'Create New Keychain' button. WARNING - doing this will replace your login keychain with a new, empty login keychain. Any passwords you had stored (i.e. for websites, file-shares, web-forms, etc.) will be lost.