Do you ever need to reset user passwords, or unlock Active Directory accounts? Is a macbook your primary desktop? If so, AD HelpDesk for OSX might be a valuable addition to your application library.
The full text of the error is:
"Unable to find the service principal requested. The service principal may have been detected incorrectly in your network. Set the 'Default Domain Controller' in preferences to try and work around this."
The suggested resolution (setting the domain controller in preferences) really does work around the issue normally, but if you have done that and are still experiencing difficulties this post will help you solve the problem completely.
If you Google “the trust relationship between this workstation and the primary domain failed”, you get plenty of information from support blogs and Microsoft articles; however, most of them ask you to rejoin your machine to the domain. That’s not always possible.