Hello there,

Is Restore previous sessions greyed out?

You could try if you can restore the session then when you copy the contents of the sessionstore.bak file(s) into this web service: https://firefox-session-restore.herokuapp.com/

Hope this helps!

First: Do not exit Firefox. If you closed Firefox, do not start it again.

Please back up your session history files to a safe location for potential recovery/salvage operations.

If Firefox is already open: You can open your current Firefox settings (AKA Firefox profile) folder using either

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

In the first table on the page, click the "Show Folder" button. This should launch a new window listing your currently active settings files.

If Firefox is not open: Type or paste the following into the Start menu search box and press Enter, then drill down into the most recently updated settings folder you find there.

%APPDATA%\Mozilla\Firefox\Profiles

In both cases: Scroll down and double-click into the sessionstore-backups folder. Save all files here to a safe location, such as your Documents folder. If not too much time has passed, we may be able to use them to recover your lost tabs.

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

• 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
• upgrade.js-build_id: the windows and tabs in the Firefox session that was live at the time of your last update

Could you take a look at what you have and the date/time of the various files to see whether you think any of them would have the missing tabs?

Note: By default, Windows hides the .js extension. To ensure that you are looking at the files I mentioned, you may want to turn off that feature. This article has the steps: http://windows.microsoft.com/en-us/windows/show-hide-file-name-extensions

You can also try to restore a previous version of the sessionstore.js file.

• Right-click: Properties > Previous Versions
• http://windows.microsoft.com/en-US/windows7/Previous-versions-of-files-frequently-asked-questions

I have a very similar problem to this. I have four windows open, with multiple tabs in all, three of the windows are working as they were before the update, but the fourth window has opened all as new tabs since switching on the PC this morning. Would this be classed as the same problem or do I need to open a new question.

It looks like the previous.js file still contains the missing tabs, but my sessionstore.bak file is dated from Oct 2014

Hi havugot1, ignore sessionstore.bak. That hasn't been used for many versions of Firefox now.

Using https://firefox-session-restore.herokuapp.com/ with the contents of the files in ...\AppData\Roaming\Mozilla\Firefox\Profiles\[ProfileName]\sessionstore-backups\ I was able to recover most of my missing pinned tabs.

Without completely resetting though, I still haven't been able to turn off grouped browsing which I suspect may have been the culprit of this issue.

Switching on my PC this morning and letting Firefox load as usual, I found that everything was back to normal. The window that had opened as new tabs had reverted back to the original.

havugot1 said

Switching on my PC this morning and letting Firefox load as usual, I found that everything was back to normal. The window that had opened as new tabs had reverted back to the original.

Today when I started it up, the fourth window was back to all new tabs :-(

today at startup all four windows loaded as they should, but, as they started to load, all tabs in all windows showed the tabs as new tabs until the loading had finished.

Hi havugot1, I don't know why that sometimes happens. Is Firefox shutting down normally or is it crashing at shutdown?

Users have reported that using the menu to exit can avoid many shutdown crashes. In other words, instead of the "red x" button:

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

jscher2000 said

Hi havugot1, I don't know why that sometimes happens. Is Firefox shutting down normally or is it crashing at shutdown?

I do not shut down any of my firefox windows/tabs, unless I have had to open a new window/tab. When I close a newly opened window or tab I always use the X and not had any problem.

When exiting my system for the night, I allow windows to close down firefox. The only recent problem I encountered was Thurs/Fri, my PC was taking a long time to shutdown, so I left it to shut itself down, but when I woke in the morning it was still at the shuting down screen. As windows had closed programs and logged off, I assumed this was a problem with my aging computer rather than a new software error.

havugot1 said

When exiting my system for the night, I allow windows to close down firefox.

Firefox sometimes needs a minute after the last window closes to update files. Perhaps that is not being completed every time, depending on what else Windows needs to do before shutting down. It would be safer to use the menu to exit if you can get used to doing that.