Long gone, I suggest working on finding the urls again, much better chance of that than getting your tabs back.

If Firefox is closed, do not open Firefox. I'll come back to you in a second.

If Firefox open, open your current Firefox settings (AKA Firefox profile) folder using either

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

In the first table on the page, click the "Show Folder" button.

In the window that launches, scroll down and double-click into the sessionstore-backups folder. Save all files here to a safe location, such as your Documents folder. If not too much time has passed, we may be able to use them to recover your lost tabs.

If Firefox is closed, type or paste the following into the Start menu search box to drill down into your profile folder:

%APPDATA%\Mozilla\Firefox\Profiles

Here you my see only one folder, in which case, click into it and then proceed as above with sessionstore-backups.

If there are multiple folders, check each one for the most up-to-date files.

The kinds of files you may find among your sessionstore files are:

• recovery.js: the windows and tabs in your currently live Firefox session (or, if Firefox is closed, your last session)
• recovery.bak: a backup copy of recovery.js
• previous.js: the windows and tabs in your last Firefox session
• upgrade.js-build_id: the windows and tabs in the Firefox session that was live at the time of your last update

Could you take a look at what you have and the date/time of the various files to see whether you think any of them would have the missing tabs?

Note: By default, Windows hides the .js extension. To ensure that you are looking at the files I mentioned, you may want to turn off that feature. This article has the steps: http://windows.microsoft.com/en-us/windows/show-hide-file-name-extensions

Whoops, on Windows XP, instead of the Start menu search box, it would be Start menu, Run dialog.

What I did, when I found this folder and saved a copy of it, was to make copies of the last upgrade file and renamed them to previous.js, recovery.js, and recovery.bak. I even rebooted after that and then restarted FF. FF restored those 3 files to their former selves (102K vs 1174K).

There must be another location that is overriding these files—maybe the registry?

What if I undo the last FF upgrade? Would that restore the tabs that were in use at that time? Then I could upgrade again after that. Just a wild thought...

I feel that we're so close and yet still unattainable. It's weird that FF still has all these empty tabs still showing, as if waiting for the boot-up to finish the job.

I wasn't intending for you to improvise, but to let me know what file looked the most promising. Could you try again using the following steps:

(1) Exit Firefox normally. During shutdown, these changes should occur:

• recovery.js is moved from the sessionstore-backups folder to the main level of the profile folder and renamed to sessionstore.js
• recovery.bak is deleted from sessionstore-backups

(2) Once Firefox has stopped updating things, rename sessionstore.js to sessionstore.old

(3) Copy in the file you want to restore (your old upgrade.js in this case) and rename it to sessionstore.js -- Windows should show it right next to sessionstore.old in alphabetical order

(4) Start Firefox and it should read the "new" sessionstore.js and restore that session -- you might still need to use Restore Previous Session if it is not restored automatically, and check Recently Closed Windows for any missing windows

Does that work for you?

Good answer, sir!!! That solved the problem without a hitch! I only lost about 2 weeks worth of tabs or less, but it's much better than losing about 3-4 years worth of work. I am so delighted—and relieved! You have made my day! Thank you so much!

I'm thinking now that I should periodically backup that session file, in case it happens again. I didn't mention it before, but I think that it's relevant now regarding browser hijacking. After FF crashed during closure, AVG wanted to upgrade, which I did, thinking that I was going to restart anyways. Upon restarting, AVG finished its update and then started FF in order to advertise its products to me. Problem is, the PCs boot-up wasn't completed yet and FF got even more tangled with empty tabs besides the AVG advertisement. In trying to clear the mess, I closed everything and did another re-boot. This time an important process failed to complete and my PC became unresponsive. I actually had to pull the power plug in order to shut the darn thing off. Booting up after that was successful, with the exception that AVG hijacked FF again, with the same empty tabs looking at me besides the AVG tab. It has been a maddening experience with this problem and it has taught me to ignore update requests from other parties when there's crashes involved. The problem of every update from every vendor is browser hijacking—even FF does it. Normally it's harmless but this case has proven that harm can be done if other issues are involved. I wonder how many other problems have been caused by browser hijacking at the wrong time? Just a thought...

Again, thank you, sir, for a job well done!

See also this extension:

• https://addons.mozilla.org/firefox/addon/session-manager/

This looks like a great extension, cor-el, and I installed it. To be frank, I am utterly amazed with the wealth of applications and flexibility with FireFox, which redeems FF from those annoying crashes. Thanks so much!