This is an odd issue. Please try clearing cache and cookies as I don't have this issue. Please also make sure that you date and time of your pc is correct as this may be the cause as well.

Check out why the site is untrusted (see the Technical details) and if this is caused by a missing intermediate certificate then see if you can install this intermediate certificate from another source.

You can retrieve the certificate and check details like who issued certificates and expiration dates of certificates.

• Click the link at the bottom of the error page: "I Understand the Risks"

Let Firefox retrieve the certificate: "Add Exception" -> "Get Certificate".

• Click the "View..." button and inspect the certificate and check who is the issuer.

You can see more Details like intermediate certificates that are used in the Details pane.

i also have this problem with firefox 22 can't install add on's because of security certificate...but also...i can't use google at all, as says the same untrusted...also facebook..(untrusted) ebay sign in (untrusted) using windows 7 fresh install.(fully updated)..no problems with clock!! but ff 22 is literally unusable...and when i did manage to get to add on page it looked like safe mode(all blue text)...it does the same when first going to ebay...i used ff as default browser..but now its intolerable.

i checked the details of the untrusted certificate....it was issued by kaspersky (my anti virus) is this the reason i can'y use ff but can use ie or chrome?

Hi Tattoo, it sounds like your Kaspersky software is intercepting secure connection so it can filter them.

You probably can turn off this feature and make your secure connections directly.

However, I do see a solution on the Kaspersky forums that could try if you want to keep this feature turned on:

• Kasprersky+Firefox+https=problem warning - Kaspersky Lab Forum

• Safe Money security certificate problem - Kaspersky Lab Forum