See if these can help;

https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

https://support.mozilla.org/en-US/kb/how-run-firefox-when-profile-missing-inaccessible

These can't get your data back, but will help in the future.

These add-ons can be a great help by backing up and restoring Firefox

FEBE (Firefox Environment Backup Extension) {web link} FEBE allows you to quickly and easily backup your Firefox extensions, history, passwords, and more. In fact, it goes beyond just backing up -- It will actually rebuild your saved files individually into installable .xpi files. It will also make backup of files that you choose.

OPIE {web link} Import/Export extension preferences

Could you start by creating a new Firefox profile. Since I don't have hands on experience with Mac, I'll refer you to our support article: Profile Manager - Create, remove or switch Firefox profiles.

When you create the new profile, please ignore the option to change the folder location. Just let Firefox choose the location, then start up in the new profile. It should be pretty much a blank installation. Let Firefox sit there for a moment while you search for your old data.

If you look inside the Old Firefox Data folder, do you see a semi-randomly-named folder with recently modified files inside?

If yes:

You can try to recover the pre-Refresh data from this folder you like. Here is how I suggest doing it:

Overview

These are the steps described in more detail below:

1. Create a new Firefox profile (you already did this)
2. Remove everything from that new profile folder
3. Copy in everything from the old profile folder

Open the New Profile folder in Finder

Firefox in the new profile should look like a factory fresh installation. Open the Troubleshooting Information page using any of these methods:

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

In the first table, click the "Show in Finder" button. Firefox will launch your brand new profile folder in a Finder window.

Leaving that folder open, switch back to Firefox, and Exit using either:

• "3-bar" menu button > "power" button
• (menu bar) File > Exit or is it Firefox > Quit on Mac?

When Firefox closes, the new profile folder should be front and center, or you can activate it.

Copy Old Data in Place of New

In that new profile folder, select all the contents and delete.

Leaving that window open, open or switch over to your Old Firefox Data folder. Drill down into your old profile folder. At this level you should see a folder named bookmarkbackups among other things.

Select everything and Copy.

Switch to the empty new profile folder in other window and Paste. This may take a minute since some of the files are large.

Start Firefox

Firefox should start up in that "new" profile with the resurrected old profile data. Success?