Hi Ken, try Recently Closed Windows or Ctrl+Shift+N.

You might also want to check Firefox View. Either:

• click the file drawer icon at the left end of the tab bar
• type or paste about:firefoxview into the address bar and press Enter to load the page

In the left column of the page, click Open Tabs. This should show and let you switch to other open windows that might not be visible on the screen.

Mr. Scher, thank you for the prompt response. And for the suggestions. I was not able to find the several dozen tabs I had open for several weeks and used on a daily basis. I was able to reopen tabs and windows from the separate webpage/tab I separate from the browser page I had open with several dozen tabs. When I closed the browser window with dozens of tabs open I did so by selecting the X icon in the far upper right hand corner and not by using the menu button (3 stacked lines) and selecting Exit. Perhaps that is why I am not able to find the other tabs. Perhaps one Browser window is open only the most recently opened window is able to reopen recently closed Windows and Tabs?

I will proceed with reviewing the History section to find the pages I had open as far back as the history is available which is the end of March. I will now create a bookmark folder for pages I want to keep open for quick access as a backup. This scenario has happened to me a twice in the last 5 months which has been quite painful. This occurred when I was prompted when an 'update' was available and I lost the tabs I had open. Perhaps without 'Exiting" first I lost the ability to re-open tabs and windows?

Thank you again for the response, Ken

Hi Ken, it's definitely safer to quit using the menu. Either:

• menu button > Exit
• (menu bar or Alt+F) File > Exit

That way, you won't have to go to History > Recently Closed Windows to recover that closed window.

By default, Firefox remembers the last 3 closed windows, so if you realize the problem right away, you can use the menu or Ctrl+Shift+N to recover. However, by now, perhaps too many other windows have opened and closed and you can't use that option.

I can suggest one other thing: when Firefox does an internal update, it usually creates a session snapshot. These aren't kept forever, but if you are looking for tabs from a few weeks ago, you can try this to get at least some of them:

(1) To open your profile folder...

You can 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 and click the "Open Folder" button. This should launch Windows' File Explorer listing the contents of your current profile folder.

(2) Copy out session history files

In your profile folder, double-click into the sessionstore-backups folder. Look for files that have this name pattern:

upgrade.jsonlz4-build_id

For example, upgrade.jsonlz4-20250430203103 is the Firefox 138.0 update from about 2 weeks ago.

(3) File Contents Export

These compressed files are a pain to view, so I created a tool on my website to list out their contents. If you want to try that, you can drag and drop one of those files onto the large box on the following page, then click the "Scrounge URLs" button:

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

If you don't get a list within 15 seconds, that probably means the script is caught in a loop. You may need to close the tab to avoid a tab crash and then try again in a new tab.

If you get a useful list, use the "Save List" button to archive it as a web page of clickable links for reference in reopening pages at your leisure.

Mr. Scher, I am several days behind responding to you. I really appreciate the additional detailed response and suggestions. Amazing. Your assessment is probably what I ran into. I had too many other windows have opened and closed and you can't use that option. As you stated, Firefox remembers the last 3 closed windows. As a safeguard, I will bookmark webpages I leave open but need to spend time to review the page before closing. I have too many webpages open for different reasons. Thank you again for the terrific assistance and guidance. We are fortunate to you assisting users in the community. Be well,

Ken