IMPORTANT: On the Export File Format page place a tick next to the option that says: "Include all certificates in the certification path if possible". Click on Next.
Posted by gwyneth on Tuesday, April 29, 2008
Have a new machine and trying to Export/Import a Thawte (or any other) Certificate? Make sure you follow these steps: https://search.thawte.com/support/ssl-digital-certificates/index?page=content&id=SO552 Else you'll end up with errors like this along the way to Importing and Using the Exported cert: - Windows does not have enough information to verify this certificate - Error -2146885628 certificate installation failed - Microsoft Outlook: Could not sign or encrypt this message because your certificate is invalid The cause in my case was that the root certificates for the CA (Thawte in this case) were not included in the certificate when I exported it. Thats the reason windows could not verify the certificate and Outlook would not send encrypted emails. Installing Thawte's root certificates (from: http://www.thawte.com/roots/) didn't help. Reinstalling my cert from the Thawte website gave me an error too. Thankfully, I hadn't deleted the original cert from my other laptop so I re-Exported the certificate correctly using the steps above. The important bit is labeled such in the steps: