about: pages are internal to the Firefox browser. Launch Firefox. In a new tab, type or paste about:profiles in the address bar and press Enter/Return You should see a page similar to the attached image.

If not, what is it that you see?

https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

Here's what I see:

(Please see attached image.)

Thank you for trying to help.

What Mac OS X version is on your wife's computer ?

Note that Firefox 78.15.0 is the last version for Mac OS X 10.9 and 10.10 and 10.11. Current releases require Mac OS X 10.12 or newer.

• https://support.mozilla.org/en-US/kb/firefox-mac-osx-users-esr

Firefox 78.15.0 on the Mozilla CDN server:

• https://download-installer.cdn.mozilla.net/pub/firefox/releases/78.15.0esr/

She's got MAC 10.0.5

She's got Firefox 36.0.4. The website said that she is up to date with that version.

Thank you.

After you get your installation straightened out there's also this - Finding your profile without opening Firefox https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data#w_finding-your-profile-without-opening-firefox

Thanks, but I already tried that, and all the examples look as if that solution is for Windows OS, not Mac.

If you open it with Mac it should automatically customize for Mac. Otherwise, you can do it manually at the upper right.

Anyway, for Mac - Finding your profile without opening Firefox

Click the Finder icon in the dock. On the menu bar, click the Go menu, hold down the option or alt key and select Library. A window will open containing your Library folder. Open the Application Support folder, then open the Firefox folder, and then the Profiles folder. Your profile folder is within this folder. If you only have one profile, its folder would have "default" in the name.

Yeah. I had found that before. But knowing where that is didn't help with solving the problem.

Firefox 36 required a minimum of Mac OS X 10.6. If your wife has at least that version, she can update to the Extended Support Release of Firefox 45:

http://archive.mozilla.org/pub/firefox/releases/45.9.0esr/mac/en-US/

That's for U.S. English. For other languages/locales, click the .. link on that page and then click into the desired folder.

But I don't think the about:profiles page was added until Firefox 47, so either way, you would still need to use the external profile manager to see whether Firefox can start up using the earlier profile.

Before doing that:

It would be a good idea to see what version of Firefox touched the profile last because there was less protection against corruption before Firefox 67. Check the compatibility.ini file in a text editor to see what version of Firefox is listed in each profile folder.

Firefox 48.0 and later required Mac OS X 10.9 at minimum to run until Fx 79.0 which requires 10.12 at minimum.

https://www.mozilla.org/firefox/45.0/system-requirements/ https://www.mozilla.org/firefox/47.0/system-requirements/ https://www.mozilla.org/firefox/48.0/system-requirements/

The Firefox 45.9.0 esr will be the most up to date (with security fixes) to run if you have Mac OS X 10.6, 10.7, 10.8

If the Firefox version you have is Firefox 36.0.4 then I agree the OS on system is at least Mac OS X 10.6 as 10.6 has been a minimum system requirement since Firefox 17.0

Does she have a Time Machine backup or other backup that could be used to restore file(s) from this backup in case the profile has been corrupted ?

Thank you to all who replied.

Thank you, especially to JScher2000 who provided a solve that worked!

I updated to the version in the link. It immediately started to download an update. Minutes later, it said I needed another update. That one produced the message that all my bookmarks would be lost if I continued.

So, I cancelled and reinstalled the first version from the link, which automatically updated to the second. Now, all I have to do is to advise my wife to ignore any further update requests.

Thank you!