Anything in either:

• "3-bar" menu button > History > Recently Closed Windows
• "Library" toolbar button > History > Recently Closed Windows
• (menu bar) History > Recently Closed Windows

The keyboard shortcut to open the most recently closed window is Ctrl+Shift+N. By default, only the last 3 closed windows are remembered.

"Some app called scrounge" sounds like my page to read out the contents of files from your sessionstore-backups folder (https://www.jeffersonscher.com/ffu/scrounger.html). This allows you to preview the contents of the file, and back it up as a clickable list of links ("Save List" button), but a website can't auto-load those new tabs into Firefox -- that requires some file swaps on disk.

As a starting point, did you find a file that has your missing tabs?

For future preventing this issue:

Use one of these to close Firefox if you are currently doing that by clicking the close X on the Firefox Title bar, especially if you have multiple windows open to prevent losing tabs in unnoticed windows.

• "3-bar" menu button -> Exit (Power button)
• Windows: File -> Exit

To: jscher2000 Hi, thanks! "Recently closed windows" in both 3bar/history and the clock(history) icon on the lower line of the menu bar have only one tab in each window. If that's the toolbar button you're referring to, then I don't know where the library is. I did find a few tabs under the Most Visited cogwheel icon.

I apologize for getting the name of scrounger wrong - the page disappeared when I clicked on an arrow or link and I didn't get back there. I did follow the directions to find a file (from an Oct update) and ran it through your software, and I did click save, but didn't know where it saved the file, or where to paste it, so hit the back arrow (&/or a link?) trying to get back to your instructions page and lost my place. If save should have put it where "Recently Closed Windows" could see it, then it didn't get there. Could you tell me where save puts the file and/or where I should copy it to? Do I need to change the name to put it higher in the queue?

To: cor-el Hi - thanks - if I ever get my tabs back - but could you tell me what the diff is between that and the x in the top R corner?

If the Scrounger saved a file without Firefox asking you for a location, use the Downloads list to find it (either click the arrow on the toolbar, or use Ctrl+J for the full list).

The file is just for your reference. If you want to roll back to that session, you need to manually replace/rename some files. cor-el can list out the details (I have to log off).

To: jscher2000 Thanks! Yes, it's in downloads. I'm eager to replace/rename as needed to get my tabs back!

I wish the 2nd Firefox window either had all the same tabs as the first or did not affect tabs at all when closed - and that "Recently Closed Windows" would retain those tabs consistently - as it is apparently intended to do and has _usually_ done in the past. I'm not the only person who's had this problem, I found lots of similar requests for help when I searched - do the engineers/programmers get notified of multiple similar requests like this??

Assuming you found the .html file, it should indicate which .jsonlz4 file it was listing out. Is that the file you want to roll back to (the .jsonlz4 file, not the HTML file)?

Here's the manual swap process to use that .jsonlz4 file:

(1) From inside Firefox, open your current Firefox settings (AKA Firefox profile) folder using either

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

In the first table on the page, find the "Profile Folder" row. On that row, click the "Open Folder" button. This should launch a File Explorer window listing the various files and folders in your profile.

(2) Leaving that window open, switch back to Firefox and Exit, either:

• "3-bar" menu button > Exit
• (menu bar) File > Exit

Pause while Firefox finishes its cleanup -- a file named sessionstore.jsonlz4 should appear in the folder.

Once Firefox has stopped updating things:

(3) Right-click sessionstore-backups and click Rename, then add OLD (sessionstore-backupsOLD) and press Enter or click away to save the change.

(4) Right-click > Rename sessionstore.jsonlz4 and click Rename, then add OLD to the file name (sessionstoreOLD.jsonlz4) and press Enter or click away to save the change.

(5) Paste in the other file you want to restore, and rename it with the name appropriate for its format:

• Compressed file such as recovery.jsonlz4 or upgrade.jsonlz4-20221104133228 => sessionstore.jsonlz4
• Uncompressed file from a decompression tool => sessionstore.js

(6) Start Firefox and it should read the swapped in sessionstore file and restore whatever was in the substitute file; if you do not have Firefox set to restore your previous windows and tabs automatically, use History > Restore Previous Session

Any luck?

Yay!!! That did it!! Thanks so much! I'm copying this solution to my how-to file in case I need it again sometime.  :-D

If you click the close X in a window then you only close this specific window and if there are other windows then only the last closed window will be restored and up to three windows can be restored via "History -> Recently Closed Tabs/Windows". This means that with each window you close the sessionstore files need to be updated. If Firefox notices that there are no more windows open then it will close Firefox on Windows and Linux (on Mac you can close all windows and leave the menu bar visible). If you use Exit/Quit then you close Firefox and all open windows at once. The latter is much safer as Firefox can close down in the proper way and only needs to update the sessionstore files once.