How to Sign Your Email with a Digital Certificate



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Mike Jetton

I'm running Mavericks and wanted to sign and encrypt via the Free Cert from Comodo. I had the same problem: "This certificate was signed by an unknown authority." in Keychain and it would not work in Mac Mail.

The problem in my opinion is because Keychain does not have the root and intermediate certificates in keychain from Comodo. I installed them from the link below and it works without error now.,1



Thanks to your comment Mike, I decided to reinstall (or install). The link you had didn't work. But I backed up my key through the browser, then double-clicked on the backed up file. That installed it. I quit mac mail, then opened it back up and was able to use the certificate. I was able to do all of this while waiting for comodo support to help through online chat. They asked me to hold on and I never heard form them again. So thank you!



This works for me on Mountain Lion; however, the certificate shows up as "This certificate was signed by an unknown authority." Not sure what the issue with that is.



Having the same issue with Mail in 10.8.2. Adding the certificate to keychain has no effect on Mail.



Hi, Can you tell me why this 'How to Sign Your Email with a Digital Certificate' doesn't seem to work in OS X 10.8.2 Mail?

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