Problem description: I had several certificates stored in Mozilla Firefox (v37), in Windows XP SP3 (32 bits). One of them expired. I have renewed the expired certificate, deleting the old one, and making a back up of the new one. After making the back up, all certificates are missing in Mozilla Firefox. If I press on Tools >> Options >> Advanced >> Certificates >> View Certificates >> Your Certificates I can't see any certificate. If I try to connect to any website where my certificates are needed, I get the error message: ssl_error_handshake_failure_alert. I have updated to Mozilla Firefox v43. I have restarted the computer. Problem is not solved. If I import my certificates using the password recorded during the backup process, I get a success message (see attached image), however the Certificate doesn't appear in the Certificate Manager of Mozilla Firefox. Where could be my certificates? Any idea will be welcome.