If these are hidden or grayed out --

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

-- check for:

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

This can help if exiting Firefox closed a popup window last rather than the window you expected to be restored.

As a general rule, it is safer to use the menu command than the X:

• menu button > Exit
• (menu bar) File > Exit

Is Firefox retaining other history from your previous session, it is only failing to restore tabs?

If Firefox is losing other history: We can help you check settings in the History section of the Settings page to make sure history isn't being deleted when you close Firefox.

If it's just tabs: We can help you check hidden preferences regarding how much is saved, and potentially clear old session history files that could be stuck/read-only.

Did you read my entire post? I said that the there was no option to restore previous sessions, and the recently closed tabs was empty.

I do not clear my history unless I'm instructed to do so. Are you implying that I have too much history?

And I have always closed my browser by closing the window. And if there was a pop-under window I would have seen it at that time and known that my tabs were gone.

Are you saying that pinned tabs are no longer saved and reopened across session unless you now exit "properly"?

In the end it appears you are saying, I'm the problem, not the something in the browser. The fine, there are several other browser to choose from. Who needs a Windows app that doesn't support 'standard' behaviors.

Did you read my entire post? I said that the there was no option to restore previous sessions, and the recently closed tabs was empty.

Yes, I did read it. Recently Closed Windows is a different list from Recently Closed Tabs.

I do not clear my history unless I'm instructed to do so. Are you implying that I have too much history?

I do NOT want you to clear history; clearing history can flush your open tabs because they are part of session history.

And I have always closed my browser by closing the window. And if there was a pop-under window I would have seen it at that time and known that my tabs were gone. Are you saying that pinned tabs are no longer saved and reopened across session unless you now exit "properly"?

I tested with using X to close a single window with a pinned tab, and it was restored normally, so as far as I can tell, that still works in Firefox 110. The reason it is less reliable is that sometimes users miss that a different window was also open and the windows are closed in the wrong order. This is when the Recently Closed Windows list can save you. It sounds like you are more aware of this issue than the average user.

In the end it appears you are saying, I'm the problem, not the something in the browser.

I did not mean to criticize you, so try to work with me here.

Let's check whether your session history files are getting updated normally so Firefox is in a position to restore them. Here's how:

(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 on that row. This should launch Windows' File Explorer listing the contents of your current profile folder.

(2) Check session history files

In your profile folder, double-click into the sessionstore-backups folder. During your session, Firefox updates the recovery.jsonlz4 file as often as every 15 seconds. The recovery.baklz4 file is the immediately previous recovery.jsonlz4 file. (These files are compressed and can't be read without decompression.)

Question: As you navigate, are these two files getting updated?

The other files you may find in this folder are:

• previous.jsonlz4: the windows and tabs from in your last Firefox session
• various upgrade.jsonlz4-build_id files: the windows and tabs in the Firefox session that was live at the time of an auto-update

(3) Changes at shutdown

Before closing Firefox, make a backup copy of recovery.jsonlz4 (for example, right-click > Copy, and then paste the copy outside of this folder somewhere, such as the Windows desktop).

When you exit Firefox normally, the following changes should take place:

In the sessionstore-backups folder:

(A) recovery.jsonlz4 and recovery.baklz4 will be removed (if Firefox crashes, they will be used in that situation)

At the main level of the profile folder (where you started before double-clicking into sessionstore-backups):

(B) Firefox will write out a sessionstore.jsonlz4 file with the final contents of your session

(C) Firefox will update the sessionCheckpoints.json file indicating that Firefox shut down normally

Question: Can you confirm that Firefox made these updates when you closed it, or did it fail to make some of the changes?

Optional File Contents Preview

If you want to view the contents of a compressed session history file, I have a tool on my website to list out their contents. If you want to try that, you can drag and drop it 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 future reference, in case no other approach is successful.

In case you use "Clear history when Firefox closes".

• do not clear the "Browsing history"

• Settings -> Privacy & Security
  Firefox will: "Use custom settings for history":
  [X] "Clear history when Firefox closes" -> Settings
• https://support.mozilla.org/en-US/kb/delete-browsing-search-download-history-firefox

• using "Clear history when Firefox closes" in Firefox 102+ honors exceptions and keeps cookies with an allow exception, previous versions removed all cookies
• clearing "Site settings" clears exceptions for cookies, images, pop-up windows, and software installation and exceptions for passwords and other website specific data

1. I successfully opened my Profile folder 2. I was able to locate both LZ4 files, one JSON and one BAK. Both appear to have the current timestamp. 3. Everything follows as you describe. Both when I use EXIT and when I use X.

Since I first reported this, there has been a small change. When I close using the X, then restart Firefox, I still only get the default home page. But now, History has "Recently closed tabs" and "Recently closed windows". In Recently closed windows there is an entry that, when clicked, will create another browser window with all the tabs

This is still not the behavior I experienced prior to the date of my initial report. I never even noticed there was an EXIT at the bottom of the before it was pointed out to me here. The fact that the behavior is no longer to my liking I think it's time to update to something more modern than a browser. I've been using it this way for over 10 years. With all the new software available I'm sure there's a web crawler that will give me exactly what I'm looking for with far less effort.

I thank you for your time, and sorry I went off on you. You're right, I'm not you average internet user. I've been a programmer for 40+ years and currently working with REST API's and JSON formatted files.

Maybe there is a hidden/off-screen window. Does your Taskbar button confirm that there is only one window when you are closing out using the X?

Keep in mind that a web browser is not a simple application, but you can have multiple windows open. Using the close X only closes this window and if this is the last window then close application is initiated that involves various steps, so if you intend to close Firefox then safest is to close via the menu then you immediately initiates the close sequence. If you want to restore the previous session most of the time then use "Restore Previous Session" as the startup setting and close all the tabs before closing Firefox if you want to discard the tabs. In case of the latter, you may want to allow extra time to let Firefox update the sessionstore files to avoid getting those tabs back.

here's what I do: 1. I open a fresh Firefox brower. At generally there are at least 12 tabs, it's been as high a 20. These tabs vary from Astronomy (NASA, James Webb, APOD) to the sciences like Quantum Magazine, Scientific American. 2. I go thru each tab searching for new items and such. 3. After I finish going thru all the tabs, I close my browser. I normally do this by hovering over the icon on my task tray so I can see if there are any unexpected windows. I then click the X on the weeds, leaving the one window I care about open. I then use X to close the finial window. So yes, I have verified that there are no underlying/unknown windows open.

Then rinse and repeat the next day.

Suddenly, this method no longer works. I start Firefox, and there's nothing but the default home page. I have the "Open previous windows and tabs" setting selected, so I expect them to be opened automatically, no extra steps necessary.

I experimented with Chrome, and it behaves as I expect. When I close and reopen. all the tabs reappear. But, this is only a temporary solution, as I'm still looking for something that will give me a digest view.

I can see that I'm not the only one that has complained about this problem. it actually appears to be an ongoing and unresolved issue. For me, it's not worth my time to diagnose. Even going thru this process has been difficult because I have too many pans on the fire.

If I may chime in, I'm having this issue, too. But, it seems to me I shouldn't have to go to the trouble of taking the above steps to get a basic feature to work properly. Will there be a fix for this in a future update?

If I may chime in, I'm having this issue, too. But, it seems to me I shouldn't have to go to the trouble of taking the above steps to get a basic feature to work properly. Will there be a fix for this in a future update?

Hi Brian, as I understand it, the problem expressed in this thread is as follows:

Starting in Firefox 110, this combination no longer works the way it did before:

(1) The "Open previous windows and tabs" is selected on the Settings page (2) You use the "X" (Close Window) button to close the last Firefox window and quit Firefox

At the next startup, Firefox no longer restores that last-closed window automatically (the window is available to manually restore under History > Recently Closed Windows).

I have not been able to replicate this problem. Or to say that another way, Firefox 111 is still working for me the way it has worked for years. This is why we posed a bunch of questions about settings, etc., to try to figure out why it worked differently on the original poster's system. We didn't find the answer, unfortunately.

Just a brief note that in a troubleshooting thread on Reddit, the problem turned out to be that one firefox.exe process kept running the background, so the session never really ended. I guess in that case, using the shortcut launched a new window into the old session (where the window was still closed):

https://old.reddit.com/r/firefox/comments/12dwcu2/all_tabs_vanishing_when_closing_window_via_x_but/

It's not clear why Firefox wasn't shutting down fully after closing all visible windows -- what was that process doing?? If this is happening to a subset of users with a specific configuration, that might help in tracking down the problem.

Hi,

I'd like to report a similar problem. 116.0.2 (64-bit), Linux Mint.

I'm embarrassed to admit I had in excess of 3000 tabs... I was planning to clean it up after moving house. I think it was all working this morning, but there was an update yesterday. This afternoon, the browser opened with a blank page. Sometimes I have a 2nd window open and forget to "X" them in the correct order, but restore using the option in the history menu. It was interesting and possibly useful to read about the difference between "X" and "Exit" in the menu - I'll give it a try in future.

Anyhow, possibly the problem was an alert box from noscript which kept appearing on restart - I take it this is treated as another window and possibly knocked my main session off the restore list. I copied my session back up folder and tried to use an old back up, but this didn't work. I was able to recover URLs by using https://www.jeffersonscher.com/ffu/scrounger.html by a contributor to this thread I think. It hung on my large file, but I had success with the fallback option of text URLs only. I think it's included all tab history, so I'm reduced to semi-manual pruning in a text editor.

I installed the "Tab Session manager" add on & loaded a small selection of URLs using "Copy All Tabs", then "X"ed the browser and restarted. Despite the new add on and a tick in the general settings of "restore tabs on start up", I still get a blank window. I'll try using the exit command and report back.

OK. I don't see my previous reply, but the page seems to note that I made one, so I'll assume it's a moderation delay. By closing with the (on my system) "Quit" command on the file menu, I was able to restart with tabs intact.

However, a second window appeared showing just the title, menu bar, tab bar and address bar. It had an identical set of tabs (except for this page - most recently opened). Then it expanded to full size, but neither window loaded anything. I closed the second window, then another, blank one opened. I "X"ed all but the first one and that then loaded (think I used stop & reload to make it happen). So I used "Quit" again and this time I got one window with tabs that proceeded to load the front one, without intervention. It did then appear to "respawn" it self, but I seem to have to the one window still. The same behaviour occurred after restarting the browser again.

So I have a back up of my old tabs and things seem to be back to normal at the moment. I hope the above is useful information and thanks for the advice on this page.

Hmmm... I see my last reply, but not the preceding one, so in summary, I had a similar problem and was unable to resolve it by moving/renaming back up session files - no session was being restored. It occurred after an update yesterday, but not until today and an empty alert box from noscript would appear on start up, leading me to suspect this window was crowding out others maybe? Not sure.

I used https://www.jeffersonscher.com/ffu/scrounger.html to extract URLs from a back up.

I installed Tab session manager, but it didn't seem to help.

OK. I don't see my previous reply, but the page seems to note that I made one, so I'll assume it's a moderation delay.

Yes, because there was a link to a non-Mozilla site (my site, not trusted by the link spam filter!).

Glad to hear your Firefox was eventually able to recover.

Regarding the Scrounger fail, yes, 3000 tabs is a lot of tabs. I test with more like 150-200 tabs. I'd love to fix it, but I'm not aware of a good way to determine what causes a tab to spin into oblivion (I'm not a professional programmer).

Hi jsher2000,

Your site was my only way to recover my tabs that I found, so thanks very much for your work. I would have had to go through them all to prune them anyway, so whether in the browser or a text editor it's the same effort. I think you included tick boxes for history and the like, so I may have another go and obtain a more compact list.

Thanks again for your help.