|Warning: If you have used S/MIME for email encryption, you should export certificates, in order to retain a backup copy, before deleting them from the browser. See: [How can I tell if I've used S/MIME for email encryption?].|
- In Internet Explorer, go to Tools > Internet Options. The following window will appear.
- Click Content to access the Content tab.
- Click Certificates. The Certificates window will appear.
- Select any extra or expired certificates and click Remove. A warning will appear.
- Click Yes, and confirm that you have one, non-expired certificate.