Hi harrymacz, let me see whether I can help.

I changed my firefox screen display from full size to a smaller size on my Mac according to your directions, and followed your directions on how to make the change apply whenever I open firefox.

What did you change? I'm familiar with the Display settings for the Mac (for example, equivalent of 1440x900, equivalent of 1280x800), but is there a Firefox-specific change?

Now I can't open google mail or any of my other now missing start up tabs because you no longer deem google (which is my default search site) a secure site. How did it google go from secure to not secure in less than two minutes?

This could occur if you use security software that filters your internet access. Once Firefox is setup to trust the fake certificates presented by that software -- it intercepts your connection and in order to read your browsing it needs to impersonate the site -- that continues unless/until there is a change in your profile, such as a Refresh. After that, the trust is broken and needs to be set up again.

I'm going to refer you to two articles:

Which error message do you get?

• What do the security warning codes mean? -- covers a range of possible reasons
• How to troubleshoot security error codes on secure websites -- this code becomes visible after you click the "Advanced" button on the error page, and the article covers the security software scenario, although it also could occur with malware or a hijacked connection setting

Do either of those help identify the reason you currently get the error pages and help solve it?

Thank you for the trouble you took in drafting your response. I tried Advanced but Firefox won't make an exception for Google. This all happened because when I downloaded and opened the new Firefox it opened in full screen, which I did not ask for and which is impossible to work with. I resized it using alt+space (I had to fire up Chrome to find this solution since firefox wouldn't open google) and in order to make the smaller screen the default size I had to "refresh" my profile, which I didn't set up in the first place. I really had to "refresh" Firefox's profile. Now the refreshed Firefox, which prohibits me from getting to my email site, is totally useless as a browser. It appears that the only solution is to put Firefox in the trash and download it again. But it's just going to give me the same full screen size that I won't have asked for. This is the same Firefox bs run-around that made me finally give it up two years ago. I'm going to put it in the trash and go back to Safari and Chrome.

This doesn't have to be complicated if you take advantage of our advice.

The Refresh moved your old profile folder to your desktop, in a folder named Old Firefox Data. In the old profile folder, there is a file named cert8.db that is set up to trust whatever "man in the middle" is reading your secure connections. You can transplant that old file into your new profile to reestablish trust. That's not the most secure thing to do -- normally I would ask you to investigate further to confirm you can trust the man in the middle -- but it's a shortcut to where you were before.

Here's how to implement it:

Open your current Firefox settings (AKA Firefox profile) folder using either

• "3-bar" menu button > "?" button > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

In the first table on the page, next to Profile Folder, click the "Show in Finder" button. This should launch a Finder window. If it lists numerous files and folders, pause there. If it only lists one or two semi-randomly-named folder, double-click the selected folder to get to the more detailed listing.

Leaving that window open, switch back to Firefox and Quit, either:

• "3-bar" menu button > "power" button
• (menu bar) Firefox > Quit

Pause while Firefox finishes its cleanup, then in the Finder window, rename cert8.db to something like OLDcert8.db.

Leaving that window open, launch the Old Firefox Data folder in a separate Finder window, double-click into your old profile folder, select cert8.db and copy it.

Switch back to your current profile folder and paste cert8.db.

Note: I've only used a Mac for a few hours, so this is the best I can do with Finder steps.

Start Firefox back up again and it should trust the same certificates as before the Refresh.