You may want to update Firefox first so you can have full access to your profiles with that message about running an older version. See: Update Firefox to the latest release.

Then:

Check whether your stuff is available in a different profile, as follows:

Profile Manager Page

Inside Firefox, type or paste about:profiles in the address bar and press Enter/Return to load it.

This page should list at least one profile and could list many. (Each profile has two folders and one or more buttons. Do not use any Remove buttons!)

The profile that Firefox is currently using will have this:

This is the profile in use and it cannot be deleted.

Do you have any other profile(s) listed on this page? If so, you can check whether it is the one you were using recently by clicking its Launch profile in new browser button.

If it isn't what you want, simply close that new window.

If it IS what you want, back on the about:profiles page, click the Set as default profile button for that profile so Firefox uses it automatically at the next startup.

Any progress so far?

Thanks jscher2000, but no joy. I have three listed profiles. The oldest one being the one that appeared after restart from Safe Mode. It's the one with all the numbers on top. The other two are newer but contain only the bookmarks from safari I transferred. Any other ideas?

Is there a way for me to restore the old Firefox by using Time Machine?

In the old profile, if you check the Restore menu, does it show any recent bookmark backups. This article has the steps to view that menu: Restore bookmarks from backup or move them to another computer.

Profile names with numbers after them usually indicate that Firefox performed a Refresh. In that case, there should be a new folder on your Mac desktop labeled Old Firefox Data. Can you find a folder like that? If so, click down into the profile folder in there and into the bookmarkbackups folder and check how recent those are.

The backups in that file show only the new iteration bookmark backups. Not the ones I lost. So I am wondering if I go into Time Machine, maybe I can go back a day or so and search for those backups inside time machine and restore those? Or copy and paste into the new Firefox?

I have to leave my computer for a while and will return in a couple hours. Thanks for any additional help you might have to offer.  Having these bookmarks and passwords and such restored is really needed.

Or can I fully uninstall Firefox and somehow reinstall from Time Machine?

The Firefox App and your Firefox data folders (profile folders) are separate. Assuming Time Machine backed up your profile folders, you should be able to restore profile folder files (or maybe entire profile folders) without making changes to your Firefox App.

I don't know Time Machine well (as a Windows user), but I think if you use a button to show the Root Directory on the about:profiles page for the "most likely" profile you then could use a menu in Finder to see what is available in Time Machine for that folder. Or something along those lines.

Oddly I no longer seem to have a Firefox folder in my application support folder.

I think by default it might be a hidden folder. Can you use the button on the about:profiles page, Root Directory row?

The screenshot shows the Mozilla folder, so you may first need to open that folder. I think that this was used in older Mac OS versions.

• ~/Library/Mozilla/Firefox/Profiles/

Reply to Everyone who has been so nice and helpful:

I opted for the nuclear option. I restored all the data on my entire OS (via Time Machine and Migration Assistant) so my computer is now back to what it was 2 days ago and all seems well and good, albeit I lost 2 days but did not lose any work, just Firefox activity. So thank you again to all the good souls who helped.

bc