Hi

Did you look at "History -> Recently Closed Tabs/Windows" to see if you could reopen that other window ?

Did you use the File menu or Exit in the "3-bar" Firefox menu button and not the close X as as only restores the last closed window ?

I think that it is always best to close Firefox from the main (most important) window via Exit/Quit to ensure that this window gets focus on the next start.

Backup the session files in the sessionstore-backups folder in the Firefox profile folder to make sure not to lose possible important session data. Do NOT close Firefox when Firefox is already running.

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 (make sure to backup the current sessionstore.jsonlz4).

You can check a recent upgrade.jsonlz4-<build_id> with this tool to see if it has your lost tabs. You can look at this tool to inspect a compressed sessionstore file.

• https://www.jeffersonscher.com/res/scrounger.html

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

• Help -> Troubleshooting Information -> Profile Folder/Directory:
  Windows: Open Folder; Linux: Open Directory; Mac: Show in Finder
• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

You can look at a utility to browse System Restore points to see if you can recover an older version of sessionstore.jsonlz4 in the main profile folder.

• https://www.nirsoft.net/utils/shadow_copy_view.html

Hi Did you look at "History -> Recently Closed Tabs/Windows" to see if you could reopen that other window ? Did you use the File menu or Exit in the "3-bar" Firefox menu button and not the close X as as only restores the last closed window ? I think that it is always best to close Firefox from the main (most important) window via Exit/Quit to ensure that this window gets focus on the next start.

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Backup the session files in the sessionstore-backups folder in the Firefox profile folder to make sure not to lose possible important session data. Do NOT close Firefox when Firefox is already running.

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 (make sure to backup the current sessionstore.jsonlz4).

You can check a recent upgrade.jsonlz4-<build_id> with this tool to see if it has your lost tabs. You can look at this tool to inspect a compressed sessionstore file.

• https://www.jeffersonscher.com/res/scrounger.html

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

• Help -> Troubleshooting Information -> Profile Folder/Directory:
  Windows: Open Folder; Linux: Open Directory; Mac: Show in Finder
• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

---

You can look at a utility to browse System Restore points to see if you can recover an older version of sessionstore.jsonlz4 in the main profile folder.

• https://www.nirsoft.net/utils/shadow_copy_view.html

YOU ARE AN ABSOLUTE STAR! THANK YOU VERY MUCH. I chose restore all windows and voila! BTW I always close Firefox via File/Exit

You are an absolute star! I used Restore all windows and voila. Thank you so much.

BTW, I always leave Firefox by using the File/Exit way. Have a good weekend