MacOS - Install Updated UserTrust Certificate



  • Oregon State University
  • MacOS versions older than Sierra


On 5/30/2020, an intermediate root certificate expired. This is not a certificate owned by OSU, but is used by older operating systems and software to confirm the validity of OSU certificates.


The best resolution is to upgrade the macOS software to at least Sierra.

As a work-around, you can install the certificate manually by following these steps:

  1. Download the certificate from
    • Note: you may need to use Chrome or Firefox to access this site
  2. Double-click on the .crt file. This should automatically launch Keychain Access. 
  3. Enter your admin credentials when prompted.
  4. The certificate will automatically install itself and be listed under System as UserTrust RSA Certificate Authority with an expiration date in 2038. However, it will have a red X on it, meaning that it is not yet trusted.
  5. Double-click on the UserTrust RSA certificate to bring up its info sheet; click on the triangle next to Trust.
  6. The first option on the info page is "When using this certificate" - set that to "Always Trust."
  7. Close the info window and enter your credentials to save the changes.
  8. The USERTrust RSA Certificate Authority should now have a blue circle with a plus sign on it.
  9. Quit out of Keychain access.


For assistance, contact the Service Desk.


Article ID: 108983
Mon 6/1/20 9:29 AM
Thu 12/31/20 12:50 PM