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after downloading version 111.01, I have lost all open tabs and history. How can I recover a couple hundred open tabs?

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  • Last reply by tekkie1

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after downloading version 111.01, I have lost all open tabs and history. How can I recover a couple hundred open tabs?

after downloading version 111.01, I have lost all open tabs and history. How can I recover a couple hundred open tabs?

Chosen solution

You can check this article.


About your lost tabs, open tabs are stored in sessionstore.jsonlz4 as part of session data.

You will normally find these files in the sessionstore-backups folder:

  • previous.jsonlz4 (cleanBackup: copy of sessionstore.jsonlz4 from previous session that was loaded successfully)
  • recovery.jsonlz4 (latest version of sessionstore.jsonlz4 written during runtime)
  • recovery.baklz4 (previous version of sessionstore.jsonlz4 written during runtime)
  • upgrade.jsonlz4-<build_id> (backup created during an upgrade of Firefox)

You can copy a file from the sessionstore-backups folder to the main profile and rename the file to sessionstore.jsonlz4 to replace the current file with Firefox closed.

  • make sure to backup the current sessionstore.jsonlz4

You can look at this tool to inspect a compressed jsonlz4 sessionstore file. This tool works locally, no uploading done.

You can use the button on the "Help -> More Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page (Root directory).

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My new home position are 4 tabs from 2015!

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Chosen Solution

You can check this article.


About your lost tabs, open tabs are stored in sessionstore.jsonlz4 as part of session data.

You will normally find these files in the sessionstore-backups folder:

  • previous.jsonlz4 (cleanBackup: copy of sessionstore.jsonlz4 from previous session that was loaded successfully)
  • recovery.jsonlz4 (latest version of sessionstore.jsonlz4 written during runtime)
  • recovery.baklz4 (previous version of sessionstore.jsonlz4 written during runtime)
  • upgrade.jsonlz4-<build_id> (backup created during an upgrade of Firefox)

You can copy a file from the sessionstore-backups folder to the main profile and rename the file to sessionstore.jsonlz4 to replace the current file with Firefox closed.

  • make sure to backup the current sessionstore.jsonlz4

You can look at this tool to inspect a compressed jsonlz4 sessionstore file. This tool works locally, no uploading done.

You can use the button on the "Help -> More Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page (Root directory).

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Maybe I panicked too soon. In history, I found a box to open previously closed window (I only had one window open; so the new version opened another window?) When I clicked that box, another window went open, Windows went crazy as Firefox used over 90% of CPU and over 80% of memory. Of course, nothing seemed to be happening for a few minutes, while windows tagged Firefox as "not responding". I walked away for a few minutes, and when I came back, my tabs were all available.

Thanx for the help you offered. I am not a computer savvy guy, just good with plastics processing technology. So I am not sure that I could have followed what you offered, and am really thankful that it was only a new opened window that confused me.