I have certificates from DOD in ".p12" format. When I tried importing it to IE browser it asks for password and imports successfully. When I try to import the same .p12 file in Firefox, it asks for password. After giving the right password it fails. Says PKCS #12 operations failed for unknown reasons. I see a thread has been opened and closed a year ago for same reason in FF support. Unfortunately no solution has been proposed. Old thread : https://support.mozilla.org/en-US/questions/927408 Let me know if you guys have a solution now.