It should not happen, but during updates, some have complained that data was missing. Up to and including finding a profile reset or refresh had been done.

Look on your desktop. Do you see a folder called; Old Firefox? Look inside. Look for the folder with the latest creation date.

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

Look at your profile. Check your bookmarks, settings, toolbars, add-ons . . . . .

Does anything look not right?

I appreciate the response!

I took a look and did not find an Old Firefox folder on my desktop.

Would it benefit me to attempt to do a profile refresh? If it can restore history, I would do so in a heartbeat, but I am not wanting to do anything that could potentially cause extensions to break or lose their own backups. The first 2 links you provided seem to indicate that when an Old Firefox folder exists, a refresh can help. And that a refresh essentially is a bit like loading up a saved file that then overwrites the current one, so to speak.

With no backup currently existing I am not sure if that would help, and since it would seem that a refresh removes addons (like the tab saving extensions I have installed from working or to stop working; they are TabSessionManager and MySessions) I would rather not risk anything else.

Is there a non-extension removing method to backup firefox? Even just creating a backup of the folder in program files and/or %appdata% from Roaming?

Unless I am misunderstanding how the refresh firefox option works when there is no pre-existing Old Firefox folder to use, my main option now seems to be simply to find a way to be able to recover in the future if this particular history-erasing issue inadvertently happens again during a future firefox update (i.e. future-proofing).

Thank you for your efforts to assist!

You would need a backup copy of places.sqlite to restore the history.

You can look at this utility to browse System Restore points to see if you can find such a backup.

• System Restore Explorer
  http://nicbedford.co.uk/software/systemrestoreexplorer/

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

• Help -> Troubleshooting Information -> Profile Directory:
  Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder
• http://kb.mozillazine.org/Profile_folder_-_Firefox

I don't think a refresh would help here.

EKenworthy said

Unless I am misunderstanding how the refresh . . .

Refreshing Firefox {web link} is a LAST RESORT ! !

Refreshing Firefox -- easily fix most problems

If you're having problems with Firefox, refreshing it can help. The refresh feature fixes many issues by restoring Firefox to its factory default state while saving your essential information like bookmarks and open tabs. Everything else, like user settings and add-ons, are removed. Note: Refresh saves your old profile to the desktop in a folder called Old Firefox.

EKenworthy said

Is there a non-extension removing method to backup firefox?

Back up and restore information in Firefox profiles.{web link} I use an add-on that makes backups of my user profile, Just In Case. Unfortunately, it is not compatible with the current Firefox.

Every now and then, open the profile folder and create a copy of the current profile as is to another location on your hard drive. This way you will have a backup.

If you do this each day, you will not lose much data. This should be done with Firefox Closed.

Note: In case you need to restore from these backups, you may need to overwrite old or corrupted files.