Sorry for the delay in responding; holidays around here.

Firefox 33 changed the names and file locations. Check for a sessionstore-backups folder to see the files that Firefox updates during your session. When Firefox exits, it should create the sessionstore.js file in the traditional location so that is available at startup.

The kinds of files you may find among your sessionstore files are:

• sessionstore.js and/or recovery.js: the windows and tabs in your currently live Firefox session (or, if Firefox is closed, your last session)
• recovery.bak: a backup copy of recovery.js
• previous.js: the windows and tabs in your last Firefox session; sessionstore.bak for pre-33 versions of Firefox
• upgrade.js-build_id: the windows and tabs in the Firefox session that was live at the time of your last update; sessionstore.bak-datetime for pre-33 versions of Firefox

Can you find anything useful?

Thanks for the response. Here's what happened. I'm using XP and I upgraded to Firefox 32 about a month ago and I backed up the last profile directory on 12/24/14 C:\Documents and Settings\Gerry Peters\Application Data\Mozilla\

Then I had some computer problems and had to revert to an Acronis image file that I made in August. So essentially it's like my C drive was now moved back in time to August, before I had the computer problems. This image had Firefox 29.

So when I reverted to this image, I went to my backup folder and I found that the sessionstore.js file was not present in the Firefox 32 backup profile folder. Firefox 32 must use a different file for saving the session and tabs. I thought maybe I should update to the latest Firefox which is 34.0.5. That didn't solve the problem.

Can you tell me which files I should copy and replace? My version of Firefox 34 doesn't have sessionstore.js in the profile folder. It does have sessionstore.bak. I also tried using all the Firefox 32 files in my backup profile directory and that didn't work Firefox 34 simply disregarded all of my sessions and tabs and opened a blank tab.

If there's no solution to this, can I install Firefox 32? Certainly those backed up files I have would work with that one.

Thanks for all your help,

Windows tends to hide "known" file extensions, making it hard to rename files. If your Windows is configured that way, you can turn on the display of all file extensions as described in this article: http://support.microsoft.com/kb/865219

Does that make it easier to find the old sessionstore.js file? If not, we can try the sessionstore.bak file. (In Firefox 32, when you start Firefox, sessionstore.js was renamed to sessionstore.bak and a new sessionstore.js was created.)

First, if you do not already have your currently active profile folder open, you can open it from inside Firefox. Either:

• "3-bar" menu button > "?" button > Troubleshooting Information
• Help menu > Troubleshooting Information
• type or past about:support in the address bar and press Enter

Keep this folder open while exiting fully out of Firefox.

After exiting, there should be a fresh sessionstore.js file in the folder (you may need to refresh using F5 if it doesn't appear in alphabetical order). Rename this file to something like sessionstore-old.js.

Then copy in the older sessionstore.js file, if you find it. Or copy in the old sessionstore.bak file and rename it to sessionstore.js.

Then you can start Firefox and try History > Restore Previous Session.

Success?

I closed Firefox and now a sessionstore.js file has been created, up until now there was only a sessionstore.bak file and it had the current date. Now I have both.

I did go to my tab groups and made some changes deleting and adding tabs. Could it be that action got Firefox to create the sessionstore.js file? In my Firefox 32 profile backup files there is a sessionstore.bak file dated 12/1/14 but no sessionstore.js.

I first renamed the files in Firefox 34 profile as you suggested and copied sessionstore.bak file and renamed it to sessionstore.js. I opened Firefox and it worked, I now have all the tabs from 12/1/14. But what happened to all the activity from 12/1/14 to 12/24/14?

Maybe during that time I made no changes to the tab groups, maybe that's why it didn't update that file, but it seems that I've lost any tabs I created during 12/1 - 12/24. Is this a bug or quirk? Or do you have any explanation why Firefox 32 didn't create a sessionstore.js and why it took Firefox 34 a few days to create one?

I have about 30 or so tab groups. I have one main tab group that I use almost all the time and use the bulk of tab groups to store topics. I like this better than using bookmarks.

Again thanks so much for your help, I'll mark this as solved after I hear from you one last time.

The current Firefox release no longer uses the sessionstore.bak file, but uses the sessionstore-backups folder instead, so that sessionstore.bak file was from the last Firefox version that used this file.

Helpful info! Ok so now that I'm using Firefox 34, if something goes haywire in the future and the menu option like "restore previous settings" doesn't solve the problem. If I have backup files of the profile directory, and I want to restore my tabs, should I only replace the "previous.js" with my backup of "previous.js"? Or should I replace all the files in the folder - sessionstore-backups? Is previous.js the most current files containing my tabs? And is recovery.js a file Firefox uses if previous.js doesn't work?

Thanks for all the help,

You need to restore the sessionstore.js file, either directly or by copying a backup from the sessionstore-backups folder to sessionstore.js.

I just discovered something very strange. When Firefox is not running sessionstore.js exists in the Profiles\t8qv6b82.default folder. Shortly after I open Firefox the sessionstore.js disappears out of the folder. Most of the time when I backup my computer data, Firefox is open, so that means it doesn't backup sessionstore.js, because that file has disappeared.

THis explains why in my old backup for Firefox 32 there was no sessionstore.js file only the sessionstore.bak file, which was 23 days old. Also with Firefox 34, I've never found sessionstore.js residing in the sessionstore-backups folder.

So in the future if I want to restore my tabs with this method and if my sessionstore.js is too old of a date to use, can I also restore by replacing the previous.js file with the most current one? Currently I have no recent sessionstore.bak file in the profile folder either.

You aren't running Firefox in Private Browsing mode?

• https://support.mozilla.org/kb/Private+Browsing

I've never used the Private Browsing mode.

Can you verify what I said about the disappearing sessionstore.js? I updated Firefox 29 to 34.0.5. I've never updated FIrefox as soon as an update came out. After hitting F5, If you don't have a sessionstore.js disappearing, I think I may reinstall from scratch.

I thought the newest versions of FIrefox didn't use sessionstore.js, but instead used sessionstore-backups folder.

sessionstore.js is still used, Only sessionstore.bak is no longer used, but there are now multiple backups in the sessionstore-backups folder instead of only one .bak file. If there is no sessionstore.js file created during the sessions then you may have disabled some prefs.

You can try this startup setting:

• Tools > Options > General > Startup: "When Firefox Starts":
  "Show my windows and tabs from last time"

• http://dutherenverseauborddelatable.wordpress.com/2014/06/26/firefox-the-browser-that-has-your-backup/

Bug 883609 - [Session Restore] Make backups useful (Firefox:Session Restore)

I checked this setting Tools > Options > General > Startup: "When Firefox Starts":

   "Show my windows and tabs from last time" 

and mine is set like that.

This is an excellent link you sent me

   http://dutherenverseauborddelatable.wordpress.com/2014/06/26/firefox-the-browser-that-has-your-backup/ 

And I think it answers my question about the disappearing and reappearing session.js file. From what this says below, I think that's the correct behavior. Please verify that your file does disappear and reappear when opening and closing Firefox.

EXCERPT During shutdown, Firefox writes a clean startup file to sessionstore.js. In most cases, this file is valid and contains the exact state of Firefox at the time of shutdown (minus some privacy filters). During startup, if sessionstore.js is valid, Firefox moves it to sessiontore-backup/previous.js. -=-=-===-=

So it seems to me that if I didn't have a backup copy of sessionstore.js, I can use the backup of previous.js to manually restore.

I know you know far more about all this than I do, so let me know if I'm correct and if your Firefox is disappearing and reappearing sessionstore.js in your installation.