UW Digital ID (Mac OS X) - Certificate Was Signed By An Untrusted Issuer

Mac OS X users may experience the following certification error when attempting to digitally sign emails:

⨂ This certificate was signed by an untrusted issuer

While the root cause of this problem is unknown, this document provides a workaround that allows your existing certificates to work as intended.


  1. Open Keychain Access: From a Finder window, navigate to ApplicationsUtilities and double-click Keychain Access.
  2. By default, you will be taken to My Certificates under the Category header, where you should see the following:
  3. Untrusted Issuer Image

  4. Click All Items under the Category header, then click inside the search bar and type "entrust".
  5. IMPORTANT: All Items must be selected for the search to return the desired results.

  6. In the new list of certificates, you should see Entrust Managed Services Commercial Public Root CA. This is the culprit.
  7. Root Certificate Image

  8. Right-click (CTRL + click) on Entrust Managed Services Commercial Public Root CA and select Delete.
  9. When prompted to confirm deletion, click Delete again.
  10. Return to My Certificates (under the Category header).
  11. Select the certificate previously in error. Under the certificate details, you should now see: This certificate is valid.

Note: If you are experiencing problems with this workaround, please contact uwdigitalid@doit.wisc.edu for assistance.

Keywords:email, outlook, yosemite, mavericks, error, signing, trusted,   Doc ID:45559
Owner:Steven T.Group:Digital ID
Created:2014-12-10 15:49 CDTUpdated:2015-08-21 14:20 CDT
Sites:Digital ID, DoIT Help Desk, DoIT Tech Store
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