If you closed and the previous sessions tabs didn't load then they are gone. It must first successfully load the tabs if you want to recover them back. But once you close before the tab loads they are gone. Only option is to look at your history to find out what you had opened but if you cleared that out then there is no finding the sessions if that was done.

If "Restore Previous Session" is grayed out, can you find any closed windows under Recently Closed Windows? Either:

• (tap Alt to activate the menu bar) History > Recently Closed Windows
• "Library" toolbar button > History > Recently Closed Windows

The recovery.bak file might date back to Firefox 55 days. The file names/formats changed in Firefox 56. The kinds of files you may find in your sessionstore-backups folder 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

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. Also, you can save the clickable list as a web page for future reference.

If you want to have Firefox use recovery.bak at the next startup, you'll need to hide all the other session history files (i.e., drag them out to another folder) and after Firefox shuts down, remove the sessionstore.jsonlz4 file from the profile folder (not the sessionstore-backups subfolder).

I tried to Scrounge URLs but I don't see any links on the site after scrounging? It just says Open Windows. Same with the html file. When I try to save as json it says "Not saving due to failure parsing JSON: SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data" Am I doing something wrong?

Hi kristenn, what does the beginning of the data look like in the box after you drop the file? A typical file would start off like this:

{"version":["sessionrestore",1],"windows":[{"tabs":[{"entries":

mozLz40{"version":["sessionrestore",1],"windows":[{"tab

I took the out mozLz40 but now when I try to save as json its says "Not saving due to failure parsing JSON: SyntaxError: JSON.parse: bad control character in string literal at line 1 column 49 of the JSON data"

If you are working with a file named recovery.bak, could you make a copy of it and rename the copy to recovery.baklz4 and then drop it on the page?

The same thing happens, it says "Not saving due to failure parsing JSON: SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data"

I think that maybe why this is happening is that I opened the .baklz4 file with notepad? Right now I have it set to open with 7zip but before I opened it with notepad the icon of the file was just white. Picture on the left is before I opened it with notepad, picture on the right is after (have it set to open with 7zip). I don't know if that has anything to do with it.

(You do not need to open a file to use the Scrounger. You can resize the windows and drag the file onto the white box and drop it.)

It doesn't matter what program you use to view a .bak (uncompressed) or .baklz4 (compressed) file, as long as you do not let the program save over the original. If Notepad or another program saved over a compressed file, it's probably unrecoverable. Do you have any unmodified files you can try?

If these tabs have been open for a long time, and you do Windows updates regularly, Windows might have saved a copy of recovery.jsonlz4, or one of the other files, in a restore point. I never recommend doing a system restore, but in Windows 7 you can check for copies this way:

Open your current Firefox settings (AKA Firefox profile) folder using either

• "3-bar" menu button > "?" Help 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. Windows Explorer should display your currently live profile folder.

Double-click into the sessionstore-backups folder. To check for old versions:

right-click recovery.jsonlz4 and choose Properties, then the "Previous Versions" tab.

Windows will search for copies of the file in restore points. If you see one that might be helpful, you can select it and use the Copy button (not Restore, do not use Restore) to save it somewhere convenient like your Desktop, and then Scrounge the file to see what is in it.

You can repeat this process with recovery.baklz4 and previous.jsonlz4.

Anything promising?

I think that Notepad might've saved over the compressed file, I don't think that I have any unmodified files, is there nothing I can do?

Your most recently opened tabs may be unrecoverable, but perhaps you can get some of the others.

Have you checked every file that you have now in the sessionstore-backups folder, and every recent file you found in a restore point?

Please scrounge the recent ones and save off lists that may be incomplete but still useful.