I picked up some malware recently and one of the many annoyances it caused was problems with Firefox’s security settings. When visiting secure (https:) web sites Firefox would say “the connection is untrusted.” When I said I wanted to trust the site and add an exception for it I would get a “sec_error_untrusted_issuer” error. When I got past the errors and added the exception the site still wouldn’t work properly — I would only see a plain text version of the secure page without images, buttons, or formatting.
After many days of grief I finally found the answer in Mozilla’s bug database: https://bugzilla.mozilla.org/show_bug.cgi?id=583191 (and yes, I got the same error when visiting Mozilla’s site). I first tried the recommended troubleshooting steps without success. I then tried the following approach, recommended by Matthias Versen. (I did this with Firefox 3.6 and Windows 7.)
- Type the phrase about:support as a URL in the Firefox address bar.
- Click the button next to Profile Directory labeled “Open Containing Folder“. That will launch Windows Explorer.
- Close Firefox.
- Locate the file cert8.db in the Windows Explorer pane you opened in step 2 and move the file to a different location (like your desktop) or rename it.
- Start Firefox again.
All I can say is that it worked for me. Maybe it will help you.