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Browser tabs do not reopen at new start of Firefox

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After having created a couple of tab groups with some of the numerous tabs that were already open in my browser (Firefox, of course) and then closing and reopening the browser shortly after, no tabs at all reopened even though this is my normal setting for Firefox: open all previous tabs when opening firefox. This setting had always worked before - as it does now with the new tabs. However, all my previous tabs as well as the freshly created groups have vanished. Do you have an explanation and ideally a way of recovering the tabs - or the groups at least? Thank you very much. Kind regards, Kerstin

After having created a couple of tab groups with some of the numerous tabs that were already open in my browser (Firefox, of course) and then closing and reopening the browser shortly after, no tabs at all reopened even though this is my normal setting for Firefox: open all previous tabs when opening firefox. This setting had always worked before - as it does now with the new tabs. However, all my previous tabs as well as the freshly created groups have vanished. Do you have an explanation and ideally a way of recovering the tabs - or the groups at least? Thank you very much. Kind regards, Kerstin

All Replies (3)

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Hi Kerstin, sorry to hear about this problem.

As a starting point, could you check either:

  • "3-bar" menu button > History > Recently Closed Windows
  • (menu bar or Alt+S) History > Recently Closed Windows

Do any windows listed here have any of your missing tabs?


If you can't get the closed window back that way, you can use Firefox View to check for a non-visible window. Here's how:

Open Firefox View using either:

  • file drawer icon at the left end of the tabs bar
  • type or paste about:firefoxview in the address bar and press Enter to load it

In the left column of the page, click Open Tabs. Firefox should present a box for each window, listing its current tabs. If you spot the missing window, try clicking one of its tabs to switch to it. This could be off-screen or on a different desktop.

Anything there?

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I have this problem, or similar. After a restart, tabs are not reopening, I have the setting on startup open previous windows and tabs

but doesn't happen

on history, recently closed tabs and windows are both grayed out,

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mgl007 said

I have this problem, or similar. After a restart, tabs are not reopening, I have the setting on startup open previous windows and tabs but doesn't happen on history, recently closed tabs and windows are both grayed out,

I assume you also do not see these or they are grayed out:

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

Is the problem only with tabs, or is your history missing as well? If more data is missing, could you check whether Firefox started up in the wrong profile? The steps are in the first section of the following article: Recover lost or missing Bookmarks.

If that is not the issue:

Could you start by making a backup of your existing session history files? 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. This should launch Windows' File Explorer listing the contents of your current profile folder.

(2) Copy out session history files

In your profile folder, double-click into the sessionstore-backups folder. Save all files here to a safe location such as your Documents folder.

(3) What files did you find?

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

  • recovery.jsonlz4: the windows and tabs in your currently live Firefox session (or, if Firefox crashed at the last shutdown and is still closed, your last session)
  • recovery.baklz4: a backup copy of recovery.jsonlz4
  • previous.jsonlz4: the windows and tabs in your last Firefox session
  • upgrade.jsonlz4-build_id: the windows and tabs in the Firefox session that was live at the time of your last update

Sometimes you can tell from the last modification time which one will have your missing tabs, but not always.

Optional File Contents Preview

These compressed files are a pain to view, so I created a tool to list out their contents. If you want to try that, you can open either of the following pages:

Drag and drop a session history file onto the large box to decompress it. Then click the "Scrounge URLs" button to extract the contents into a readable format.

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.

If you decide you want to roll your Firefox back to one of the older sessions, see the following articles for the steps: How to restore a browsing session from backup.