Email Certificate Comodo

The information for Comodo (recently rebranded as Sectigo) may be outdated. Contact Sectigo for updated instructions.

Below are instructions for obtaining and backing up a Comodo Email Certificate using the Mozilla Firefox browser (recommended). These instructions are for the personal certificate. The process for a business certificate should be similar. We do not recommend Google Chrome because we have had trouble installing Comodo certificates with it.

Comodo links:

To install the certificate, see Email Certificate Install. If you need to delete a Comodo certificate, see Email Certificate Revoke.

  1. In the Mozilla Firefox browser, go to the Comodo certificate page:
  2. Click Free Email Certificate. The one page application will display.
  3. Fill out the application.

    IMPORTANT: Remember the Revocation Password you enter. It is used to delete the certificate in case you need to recreate it. For example, if you created your certificate in Google Chrome by accident, then you can revoke the certificate and create a new certificate using one of the recommended browsers. Once you have filled in the required fields, click Next >.

  4. If the certificate creation was successful, you will see a message similar to the following:
  5. If you use a web email application, open your email client in a new tab of the Mozilla Firefox browser, then locate and open the registration email sent from Comodo. If you use a desktop email client, make sure Mozilla Firefox is your default browser before opening the registration email.

    IMPORTANT: You must open your email from the same browser that you applied for your certificate.

  6. Click Click & Install Comodo Email Certificate.
    Note: If you used Google Chrome, then your browser may crash during this step, in which case the certificate will fail to install.

  7. Click OK.
  8. Open Mozilla Tools.
  9. Click Options.
  10. Click on Advanced (at the top), then the Certificates tab.
  11. Click View Certificates.
  12. Select your email certificate and click Backup.
  13. Browse to the location where you want to save your email certificate. Use your email address as the file name. Save the file with extension .p12. Click Save.
  14. Type the password that will lock the certificate file, then click OK.

Your certificate backup is now complete. If someone else get this certificate file from you and they also know the password to unlock it, they will be able to read your encrypted messages.