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I want to restore the tabs from my previous session, but Firefox won't let me

  • 3 replies
  • 2 have this problem
  • 728 views
  • Last reply by Robbie

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For reasons unbeknownst to me*, Firefox started without restoring the tabs from my previous session. Exploring the forum for help, I found that menu "Help" > "Troubleshooting Information" will lead to a page on which one can find the profile folder, which in turn contains a folder called "sessionstore-backup," in which Firefox keeps a history of previous sessions' tabs.

While none of the files in that folder are intelligible, I can see from text snippets that a file called "upgrade.jsonlz4-20191202093317" is the only one that potentially holds a backup of my tabs. This file is just twelve days old. However, I cannot find a way to restore the tabs from that file as Firefox just keeps ignoring any changes that I make to the files name and folder contents. How can I restore my tabs from that file?

  • ) There was no obvious crash, though Firefox just did not automatically load upon restarting my Macbook, which is always running the latest version of any software installed. This is nothing unusual in my experience, as it keeps happening about once a month.

Chosen solution

If your Firefox is set to restore every time, then after you exit out, either:

  • your sessionstore-backups folder should have a recovery.jsonlz4 file, or
  • your profile folder (up a level from sessionstore-backups) should have a sessionstore.jsonlz4 file

So in order to fool Firefox into restoring an older session history file, you replace the one it is looking for with the old one, and give it the same name.


Here's an old write-up for reference -- I haven't had a Mac for a couple years and the folder may vary with automatic restore:

To try swapping in a session history file from your backup folder so Firefox will load it, the standard "manual swap" method is as follows (assuming Firefox is still running):

(1) From inside Firefox, 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 in Finder" button. This should launch a Finder window listing the various files and folders in your profile.

If Firefox has selected the icon for your profile folder but not actually opened the folder, double-click the icon to open it.

(2) Leaving that window open, switch back to Firefox and Quit, either:

  • "3-bar" menu button > "power" button
  • (menu bar) Firefox > Quit Firefox

Pause while Firefox finishes its cleanup -- these changes should occur:

  • recovery.jsonlz4 is moved from the sessionstore-backups folder to the main level of the profile folder and renamed to sessionstore.jsonlz4
  • recovery.baklz4 is deleted from sessionstore-backups

(3) Once Firefox has stopped updating things, while viewing the main level of the profile folder, rename sessionstore.jsonlz4 to sessionstoreOLD.jsonlz4

(4) Copy in the other file you want to restore, and rename it to sessionstore.jsonlz4 -- after the rename, Finder should show it right next to sessionstoreOLD.jsonlz4 in alphabetical order (if it works like Windows)

(5) Start Firefox and it should read the swapped in sessionstore.jsonlz4 and restore whatever was in the substitute file; if you do not have Firefox set to restore your previous windows and tabs automatically, use History > Restore Previous Session

Any luck?

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All Replies (3)

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UPDATE: Jefferson Scher posted a link to his page that where you can decode those backup files. That's great, thanks Jeff!

https://support.mozilla.org/en-US/questions/1204253#answer-1075873

https://www.jeffersonscher.com/ffu/scrounger.html

Now what is missing is functionality in Firefox to automatically restore this without the need to manually open each and every link.

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Chosen Solution

If your Firefox is set to restore every time, then after you exit out, either:

  • your sessionstore-backups folder should have a recovery.jsonlz4 file, or
  • your profile folder (up a level from sessionstore-backups) should have a sessionstore.jsonlz4 file

So in order to fool Firefox into restoring an older session history file, you replace the one it is looking for with the old one, and give it the same name.


Here's an old write-up for reference -- I haven't had a Mac for a couple years and the folder may vary with automatic restore:

To try swapping in a session history file from your backup folder so Firefox will load it, the standard "manual swap" method is as follows (assuming Firefox is still running):

(1) From inside Firefox, 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 in Finder" button. This should launch a Finder window listing the various files and folders in your profile.

If Firefox has selected the icon for your profile folder but not actually opened the folder, double-click the icon to open it.

(2) Leaving that window open, switch back to Firefox and Quit, either:

  • "3-bar" menu button > "power" button
  • (menu bar) Firefox > Quit Firefox

Pause while Firefox finishes its cleanup -- these changes should occur:

  • recovery.jsonlz4 is moved from the sessionstore-backups folder to the main level of the profile folder and renamed to sessionstore.jsonlz4
  • recovery.baklz4 is deleted from sessionstore-backups

(3) Once Firefox has stopped updating things, while viewing the main level of the profile folder, rename sessionstore.jsonlz4 to sessionstoreOLD.jsonlz4

(4) Copy in the other file you want to restore, and rename it to sessionstore.jsonlz4 -- after the rename, Finder should show it right next to sessionstoreOLD.jsonlz4 in alphabetical order (if it works like Windows)

(5) Start Firefox and it should read the swapped in sessionstore.jsonlz4 and restore whatever was in the substitute file; if you do not have Firefox set to restore your previous windows and tabs automatically, use History > Restore Previous Session

Any luck?

Modified by jscher2000

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That worked perfectly, thanks!