Does the History menu have "Restore Previous Session" and, if so, does it help?

If that is grayed out or doesn't help, let's back up a few files. Here's how:

You can 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 "Open Folder" button.

In your profile folder, 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.

What files did you find?

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 crashed at the last shutdown and is still 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

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: https://www.bleepingcomputer.com/tutorials/how-to-show-file-extensions-in-windows/

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? To view the contents of a session history file as a page of links, you can drag and drop it onto this tool:

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

That's on my site, so if there is a problem with it, please let me know.

Since you lost other profile data such as history, and perhaps also settings and add-ons, here's another thing to consider:

Possibly this is a new profile that Firefox created due to the crash?

If you haven't already, before doing any file moves/deletes/reinstalls, you may want to do a normal system shutdown and startup to release any file locks and complete any pending updates. One user reported it took three shutdown/restarts to sort out his issues.

If your data does not magically reappear, the most likely scenarios for complete data loss are:

(1) A Refresh started but the migration of data from your old profile to your new profile was incomplete, or
(2) Your old profile was locked, so Firefox ignored it and created a new one.

Here's how to investigate those two possibilities:

Did Firefox perform a Refresh?

Unless it was interrupted in progress, you should find a folder on your desktop named Old Firefox Data. Inside would be a semi-randomly-named folder with freshly updated files. Do you see anything like that?

If so, we'll suggest how to rescue key files or completely restore the earlier profile folder.

If not...

Does the Profile Manager list your immediately previous profile folder?

To check on that, inside Firefox, type or paste about:profiles in the address bar and press Enter/Return to load it.

This page should list all the profiles Firefox is currently aware of. If you see a profile that is not currently set as default that looks promising, scroll down to it and click the Set as default profile button below that profile, then scroll back up and click the Restart normally button. (There are some other buttons, but I think those are still "under construction" so please ignore them.)

Firefox should exit and then start up using the other profile. Is that the right one?

If it's not there...

Did Firefox orphan your old profile folder?

Here's how to check whether there are additional profile folders in the standard location in addition to the one you're using. Start by opening your current 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/Return

In the first table on the page, click the "Open Folder" button, to launch a new window listing various files and folders in Windows Explorer.

In the Windows Explorer address bar, click the capitalized word Profiles to move up one level in the folder hierarchy. More than one folder here by any chance? Do the files in those folders look like they were last updated around the time of the update?

If you've got any promising looking folders, we can discuss next steps to recover use of them.

Thank you, that scrounger program of yours was helpful. Unfortunately, the latest upgrade.js file was from last month, so probably missing a few tabs.

As for the second reply, doesn't seem like it created a second profile. I was wrong about everything being deleted. Add-ons are there, settings seem the same. Actually, I think ONLY History disappeared. In fact, I'm checking History right now and it's still blank despite having visited a few sites already.

Anyway, went through the questions and they're all "No" except for the last one. There's a second folder in the Profiles folder, but it doesn't look promising. It just has an Extensions folder with something from Avira.

Edit: Gave FF a little update and unnecessary refresh, and History seems to be working again. Unless you have any ideas on how to retrieve more recent tabs, then I'll be marking this as solved. Thanks a lot, btw. Much appreciated.

One other thing you might check. Windows 7 may capture copies of your session history files from time to time in restore points. I never recommend using system restore for this purpose, but you can look for an individual file using the "Previous Versions" tab as follows:

right-click recovery.js or another session history file, then click Properties

When you click the Previous Versions tab, it should search in restore points for any copies of the file. If the date/time looks promising, you can use the Copy button to save it to a neutral location (where Firefox won't overwrite it).

You also can check sessionstore.js at the main level of the profile folder when Firefox is closed.

Anything more recent?

If there was a chance of that working, I ruined it by refreshing Firefox. Every file mentioned was created yesterday and it looks like no previous versions survived. Heh, oh well. Thanks anyway.

Refresh moves your old profile folder to the Windows Desktop inside an Old Firefox Data folder. Does it work on any of the files in there?

Oh, there it is. Hmm, no previous versions either. I do have System Restore turned on, so not sure what happened there. Am I missing something? Perhaps another setting I switched off. I don't remember anything ever appearing under Previous Versions for any file I've ever tried.

The problem might be that the folder path has changed from its original location. There is a third party tool to dig around in restore points. They are usually created when Windows does updates, so when that was can be quite variable.

• Set Windows to show hidden files: https://support.microsoft.com/en-us/help/14201/windows-show-hidden-files
• Then try: http://nicbedford.co.uk/software/systemrestoreexplorer/

Assuming there is a recent restore point, dig down along the usual path:

C:\Users\username\AppData\Roaming\Mozilla\Firefox\Profiles

to the former location of the folder now in Old Firefox Data.