If you open the menu, go to Library, History, Recently Closed Windows, does it offer to restore the tabs there?

If you can, you probably shouldn't use the "force stop" to stop programs, since it doesn't give them a chance to save any information, and you risk losing your tabs. In Firefox, try using the menu then Quit.

Backup the session files in the sessionstore-backups folder in the Firefox Profile Folder to make sure not to lose possible important session data. Do NOT close Firefox when Firefox is already running.

You will normally find these files in the sessionstore-backups folder:

• previous.jsonlz4 (cleanBackup: copy of sessionstore.jsonlz4 from previous session that was loaded successfully)
• recovery.jsonlz4 (latest version of sessionstore.jsonlz4 written during runtime)
• recovery.baklz4 (previous version of sessionstore.jsonlz4 written during runtime)
• upgrade.jsonlz4-<build_id> (backup created during an upgrade of Firefox)

You can copy a file from the sessionstore-backups folder to the main profile and rename the file to sessionstore.jsonlz4 to replace the current file (make sure to backup the current sessionstore.jsonlz4).

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 Folder/Directory:
  Windows: Open Folder; Linux: Open Directory; Mac: Show in Finder
• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

Are you referring to the Menu at the top that starts with "File" then "Edit" then "View" etc.? Because there is no "Library" option... After the "View" option there is a "History" menu. But I've looked through that and there is no history of any of my "restore last session". Is the "Library" option hidden somewhere else in Firefox? Thanks for helping by the way... (I have been force stopping through task manager for years and Firefox has been flawless at recovering my tabs - it is only when I forgot to do this and just shut off the computer without closing Firefox that I lost ALL my tabs...)

I'm learning...but only a little... So I've managed to find the "session store backups" from the windows prompt instructions on the Firefox website thanks to you. So thank you for that, (Thank you for everything by the way). I would have not have found them otherwise. However... the rest of the instructions I am stumped on completely. Particularly this part which I know is important :

"You can copy a file from the sessionstore-backups folder to the main profile and rename the file to sessionstore.jsonlz4 to replace the current file (make sure to backup the current sessionstore.jsonlz4). "

but I have no idea what is meant by "Main profile", or which of the files (I am going to include in a Picture) is to be copied or how and and what point do I "rename" a file in this process. Its all gibberish to me from there...

I am somewhat computer illiterate and really need someone to walk me through this process...

So here's my suggestion: I am set up to e-transer through my bank to any e-mail and so I propose that I'll pay you whatever you feel is comfortable for your time for this tutorial (name your price) and hopefully we can set up a time to call and do this over the phone. Of course I'll pay for the long distance fee by making the call myself...or maybe Skype... Anyway, I feel you're getting me closer to it because in that folder I'm seeing another lost session from years ago that I thought I also lost but maybe it is retrievable after all... Very hopeful, very grateful. So name your price and contact me at [email] or at [phone number] and I'll call you right back.

OR...wouldn't it be nice to have a website where you can talk to a person live and walk you through these matters live and you can pay them for their time (or maybe one exists already you know of...) Anyways money is no issue if you can help me solve this problem

And finally here is the picture of the files I found in the session

Thanks again. Peace.

Hi bergerdani, I hope you copied those files somewhere safe that Firefox won't overwrite.

What is strange about that screenshot is you have .js files -- last used in Firefox 55 -- with very current modification dates. Were those in there when you found the folder?

To preview the contents of a session history file, you can use a tool on my site:

https://www.jeffersonscher.com/ffu/scrounger.html

After loading in one of your recent files (such as previous.jsonlz4), click the Scrounge URLs button to see what is listed. Can you find a file that has what you're missing?