This problem is on your Windows 8.1 system?

Could you check whether either of these are available (not grayed out or missing):

• "3-bar" menu button > Restore Previous Session
• (menu bar) History > Restore Previous Session

If they are grayed or missing, check either:

• "Library" toolbar button > History > Recently Closed Windows (and within each restored window, Recently Closed Tabs)
• (menu bar) History > Recently Closed Windows (and within each restored window, Recently Closed Tabs)

If that doesn't help...

Firefox creates numerous session history files, but because session history is only for the immediately previous session, it is unfortunately too easy to lose it. Could you start by making a backup of your existing session history files? Here's how:

Do not exit Firefox, or if you closed it, don't re-open it.

(1) To open your profile folder...

If Firefox is still running:

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" (or "Show in Finder") button.

If Firefox is closed:

Type or paste the following into the Windows Run dialog or the system search box and press Enter to launch Windows Explorer:

%APPDATA%\Mozilla\Firefox\Profiles

In that folder, do you see a semi-randomly-named folder? If so, click into it. If you find multiple such folders, find the one that was most recently updated.

(2) Copy out session history files

In your profile folder, double-click into the sessionstore-backups folder. Save all files here to a safe location such as your Documents folder.

(3) What files did you find?

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

• recovery.jsonlz4: 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.baklz4: a backup copy of recovery.jsonlz4
• previous.jsonlz4: the windows and tabs in your last Firefox session
• upgrade.jsonlz4-build_id: the windows and tabs in the Firefox session that was live at the time of your last update
• various .js files from Firefox 55 or earlier

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 preview the contents of a file, you can drag and drop it onto this page, then click Scrounge URLs: https://www.jeffersonscher.com/res/scrounger.html

That tool is on my site, so please let me know if it doesn't work for you.

Thanks for the answer but the problem occurred on firefox android do you think this can be applied to android system also?

Actually, I have no idea how Android session data is stored. Sorry.

tej3 said

I had about 100+ tabs in firefox (I know thats a lot but all of them were very important) opened from the past week, the session used restore all the tabs every time I opened Firefox but, Today suddenly it wiped off all the tabs and also the history isn't showing any of the tabs. is there any way I can restore all those tabs? (Last session in history is showing only two tabs) plz help those were very important.

I am also having this problem with my android firefox! Because firefox was working bad, I tried a new installation and then all the tabs were away! This is really bad!

dormari99 said

I am also having this problem with my android firefox! Because firefox was working bad, I tried a new installation and then all the tabs were away! This is really bad!

I think uninstalling an Android app removes its data files, so that would explain the problem in that case. I don't know whether there is a way to back them up before uninstalling and then restore them afterwards. They probably are in a folder that is off limits to ordinary file explorers?

Apparently in the Android version Firefox doesn't create any backup folder for tabs so there is no way tabs can be restored however for future you can do one thing install any ram management app and see if it gives an option to lock the app in ram that is it is always running in the background that way you will never loose your tabs unless you uninstall any of the apps or use a xiaomi phone which has that option in its miui skin.

Hi

Firefox for Android works very differently to Firefox on the desktop. If you uninstall the app, you will lose saved data and settings.