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After upgrade, Firefox has lost my tabs. When I restore sessionstore.js, Friefox ignores or overwrites it. How can I get it to load my tabs from the backup files?

  • 6 replies
  • 33 have this problem
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  • Last reply by Marco1

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After I upgraded, Firefox opened to the start page even though my home page is set to Show my Windows and tabs from last time. I have tried restoring sessionstore.js from a backup, but nothing I do can prevent Firefox from opening to the Mozilla home page. What happened? How do I restore my tabs?

After I upgraded, Firefox opened to the start page even though my home page is set to Show my Windows and tabs from last time. I have tried restoring sessionstore.js from a backup, but nothing I do can prevent Firefox from opening to the Mozilla home page. What happened? How do I restore my tabs?

All Replies (6)

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see https://support.mozilla.com/en-US/questions/841322

Use File > Exit to close Firefox

To recover as much as you can

  1. Open History menu (Alt to show menus if don;t show them)
  2. Restore Previous Session
  3. Recently Closed Windows > individual or Restore all windows
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Restore previous session, recently closed tabs and recently closed windows are all greyed out. No love there. Sorry.

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If you want Firefox to open that session then try to select :

  • Tools > Options > General > Startup: "When Firefox Starts": "Show my windows and tabs from last time"
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This was how Firefox was set to begin with. As far as I know, that setting has never changed. Firefox just doesn't follow this command.

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I had the same problem. It seems Firefox cannot handle the sessionstore.js if it is very big. My was nearly 170 MB big! I didn't tried to understand the file format but it seems the important part is before the string "_closedTabs". I removed everything from there to the end and added the corresponding end of a fresh sessionstore.js. Then I tried to start Firefox again, it computed some time (maybe to restore the essential part of the end) and then I had my tabs back :-) Now the size of my sessionstore.js is 785 KB.

If you have also such a big file, you probably don't want to use an editor to remove the big part. I did it with sed in the command line of a Linux:

sed 's/_closedTabs.*//g' sessionstore.bak > sessionstore.restore

I'm not an expert in command line tools and I bet there is a better way, but it finished fast enough.

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My sessionstore.js was just 602 KB, but I had lost my open tabs anyway. I have found a similar solution as nexxTM.

After discovering the loss, I immediately made a copy of sessionstore.js. I opened it in a file editor. Unreadable. I found out it is in JSON format, so I downloaded a JSON plugin for my text editor (in my case, JSON Viewer for Notepad++) and formatted it. I became accustomed with the file format to some degree. I realized all my lost tabs were in a section _closedWindows. I cut its content and pasted it to the section windows, removing the old content. Then I undid the formatting, because Firefox cannot handle it. I needed to remove all new line and tab characters. In my case, this was a safe operation as the original file did not contain these characters. Then I moved the repaired file to the profile directory and started Firefox. My tabs were back.

Modified by Marco1