Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

One of my windows is gone, complete with tabs. I want the tabs back, but they are not listed in Recently Closed (neither Windows nor Tabs).

  • 27 replies
  • 1 has this problem
  • Last reply by Egmonster

more options

I just spent over an hour on this "Fill in details" step, and suddenly it's Access Denied. Firefox doesn't have a copy of this document in its cache. Please tell me you have the document! I am in tears now.

Chosen solution

For about:config, the separator is a colon, not a period. That should get around it being converted to a web address.

On the History menu, is "Restore Previous Session" grayed out or enabled?

If it's enabled, and you have no currently open tabs you don't mind losing, give it a try to see whether that auto-restores last night's previous.js.

If it's grayed out, you'll need to do the switch the hard way... The usual method is as follows:

(1) Exit Firefox normally, and these changes should occur:

  • recovery.js is moved from the sessionstore-backups folder to the main level of the profile folder and renamed to sessionstore.js
  • recovery.bak is deleted from sessionstore-backups

(2) Once Firefox has stopped updating things, rename sessionstore.js to sessionstore.old

(3) Copy in the file you want to restore (your old previous.js in this case) and rename it to sessionstore.js -- Windows should show it right next to sessionstore.old in alphabetical order

(4) Start Firefox and it should read sessionstore.js and restore whatever was in previous.js -- you might still need to check Recently Closed Windows for the missing window

Does that work for you?

Read this answer in context 👍 1

All Replies (20)

more options

Why? Why? I think it was several hours I spent trying to condense the situation into words. I don't know what happened but it's gone. This Firefox support is the most torturous process I've seen in a while, with endless loops of "create a support account"/"I already have an account"/Login/"create a support account" and then asking for details on a form that vanishes and blanks itself, erasing my work from YOUR browser cache, then sending a confirmation by email which I need to open on the device that doesn't have Firefox.

more options

Hello Egmonster!

No need for tears! I'm so sorry our site lost the details you worked so hard to add. We appreciate that you went into that much detail! The title already tells me a lot about your situation so let's start there.

One issue is that if you close Firefox after losing your tabs or windows, it makes it harder to recover them. So do NOT close Firefox again. Hopefully you haven't since you made this post. If you have not opened Firefox twice since losing your tabs, I believe we can recover them.

First, find your profile folder: Profiles - Where Firefox stores your bookmarks, passwords and other user data

You will need to go to your Firefox profile folder and look for 2 files called sessionstore.js & sessionstore.bak (if they are not present, that's ok) and a folder called sessionstore-backups (mandatory! You must copy this folder). You will need to copy these to safe location like My Documents. Do this immediately so we can have a chance to recover your data. Do not close Firefox during this process. Doing so will cause Firefox to overwrite the backup of your tabs.

more options

I do have Firefox set to restore prior windows and tabs each time it starts. I did find the Profile folder and copy the sessionstore-backups folder but there is no current sessionstore.bak file in it or the Profile folder (just one a year old, and sessionstore-1.js is even older)

more options

I haven't closed Firefox once since it happened.

more options

(How do I prevent cross-posting like we did above, when I was saying what I found in the profile folder while you were telling me how to look in the profile folder?)

more options

Good! That's luck on our side! :D

Ignore the sessionstore.js and .bak files then. Excellent job checking the modfied timestamp. That indicates it's too old to help us here as you said.

Also I have been complaining for the longest the way Firefox backs up tabs and windows is horrible for users looking to recover lost tabs/windows. Since opening Firefox a 2nd time erases the backups. Ridiculous! Anyway that's something I'll need to file a bug for. :)

But back to your issue! Please look inside the copied sessionrestore-backups folder and tell me the sizes and timestamps of those files. We will want to find the fattest file in the bunch and the one with a timestamp of before when the tabs were lost.

more options

About the cross-posting, I was typing that reply and sent it right as you made your 'endless loops" post.

My post went thru first and then you responded 4 mins later about what I asked you to check. So it seems everything happened in order. Seems a bit fast since we're both actively trying to fix the problem. :)

Modified by NoahSUMO

more options

I don't need anything from that session saved. I bookmarked anything that mattered. There is a chance the window might come back by itself but I want to make sure I can get back to how it was when I shut down yesterday. So although I opened and closed other tabs and windows (all duly recorded in History & Recently Closed) I haven't touched the two remaining of my three usual windows with my long-term tabs.

more options

Is there way to see whether you've posted before I send? I would like to reply to the last post, not the last-before-I-started-writing.

more options

I don't think the window will come back by itself. Especially if it's not listed in "Recently Closed Windows". If it is listed, just click it and it will be restored.

Otherwise, to get it back, you'll need to copy over the oldest of the files in the sessionstore-backups folder to the actual sessionstore-backups folder. After renaming or moving the current files there, so that Firefox can properly detect that file and restore from it.

Please make sure you have backed up everything properly here. Even back it up a 2nd time if you must. I don't want to hear about any more data loss. I'm paranoid about it myself so before you do anything else make sure you've backed it all up. To protect your 2 windows with long-term tabs.

Modified by NoahSUMO

more options

Egmonster said

Is there way to see whether you've posted before I send? I would like to reply to the last post, not the last-before-I-started-writing.

The only way to do that would be to load this page in Firefox and keep refreshing it. Or check your email, it will send you a notification that I have responded.

more options

Then if I want to see whether you've replied while I was writing, I have to (1) select my writing in this box, (2) copy it, (3) refresh the page (I was afraid it would duplicate a previous post or send my incomplete text, but it didn't seem to do that, so I guess I don't need to clear the box before refreshing) then (4) paste my text into the now-empty box, (5) resume writing, and finally (6) repeat steps 1-4 (and 5 if necessary, followed by 1-4 again) before Posting Reply? User-friendly! Why not have the page refresh in real time or at least without wiping the text box?

more options

The sessionstore-backups folder has 6 files (without capitalisation): Previous.js 803 kB Recovery.bak 595 kB Recovery.js 595 kB all from last night Three upgrade.js- files, the most recent recent ten days old

more options

Sorry. The first file is from last night. The next two are from this afternoon. In the copy in My Documents folder they're from right after it happened.

more options

Oh yes, and I haven't much time left. I'd like to shut down the computer before I go out.

more options

Judging from the time stamps on the files in the backup, is there one you think has the best chance of having the missing window? That would be the one to try swapping in for your current session history file. Unfortunately, it is a matter of either/or, there's no way to merge them together.

Or since you need to leave, that backup should still be there for you when you start up again.

more options

Two other thoughts:

(1) For best results, shut down using the menu to Exit and not the red X button on the title bar or allowing Windows to shut down Firefox. This gives you a better shot at a complete restore and Firefox completing its shutdown tasks properly. Either:

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

(2) To increase the number of closed windows retained in the session history files, you can adjust this hidden setting:

  • In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful.
  • In the search box above the list, type or paste sess and pause while the list is filtered
  • Double-click the browser.sessionstore.max_windows_undo preference and enter the desired value, for example 5 if you might have as many as 5 windows open in a session; I set this to 10 myself.
more options

Noah_SUMO said

you'll need to copy over the oldest of the files in the sessionstore-backups folder to the actual sessionstore-backups folder. After renaming or moving the current files there, so that Firefox can properly detect that file and restore from it. Please make sure you have backed up everything properly here.

I don't quite follow. I'm to do something with previous.js (803 kB, last night)? That one's the same (name, size, date) in the copy as the active sessionstore-backups folder. Do what?

I would be happy if it went back to the state in which it shut down last night. Is previous.js enough to make that happen?

I am not sure whether I have everything. That's why I left Firefox running. But I have to go meet my son in minutes. I will leave the *#@* computer running if I *@+?#@* must.

I will be back late tonight or in the morning.

more options

Are there other files I need to copy before shut down?

more options

Firefox turns it to www.about.config and can't find it!

  1. 1
  2. 2