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Firefox sync sessions?

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  • Last reply by cor-el

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I'm confused about sync when it comes to sessions. Sessions is not one of the options.

A few days ago, I open Firefox and my profile was broken. Nothing worked in the way of toolbar addon buttons, contest menus, etc. I narrowed the problem down to the session store files.

The session was still present. I could scroll thru it, and select tabs, but hat was about it. Fortunately I was able to get things back working again in a fresh profile, but it was a tricky exercise.

My desktop sessions sync with my phone. Is the re a way to perhaps sync sessions, and do it recursively so you don't get a mess with duplicates and discarded tabs?

I used to to use Tab Session Manager until a couple years ago when it began destroying sessions, and there was no way to retrieve them. Even the supposedly repaired version couldn't reverse the process. Had something to do with the sessionstore-backups folder, so I don't know if I can trust it now.

I'm confused about sync when it comes to sessions. Sessions is not one of the options. A few days ago, I open Firefox and my profile was broken. Nothing worked in the way of toolbar addon buttons, contest menus, etc. I narrowed the problem down to the session store files. The session was still present. I could scroll thru it, and select tabs, but hat was about it. Fortunately I was able to get things back working again in a fresh profile, but it was a tricky exercise. My desktop sessions sync with my phone. Is the re a way to perhaps sync sessions, and do it recursively so you don't get a mess with duplicates and discarded tabs? I used to to use Tab Session Manager until a couple years ago when it began destroying sessions, and there was no way to retrieve them. Even the supposedly repaired version couldn't reverse the process. Had something to do with the sessionstore-backups folder, so I don't know if I can trust it now.

Modified by noel_envode

All Replies (6)

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Did you use the Firefox refresh feature in Firefox ? In that case you might still have useful session data in the sessionstore-backups folder in the "Old Firefox Data" folder on the desktop.

You can try to restore a recent upgrade.jsonlz4-<build_id> when available or use a utility to browse Windows System Restore points to see if you can find a recent sessionstore.jsonlz4 file.

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 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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cor-el said

Did you use the Firefox refresh feature in Firefox ? In that case you might still have useful session data in the sessionstore-backups folder in the "Old Firefox Data" folder on the desktop
I use the Firefox profile manager. Periodically I will recreate an existing profile (I have a basic profile template from which I build different profiles with specific content) to kinda "freshen" things up. In those cases, I transfer a group files from the old profile to the new. My problem this time was that when I encountered the broken profile, I tried to transfer the same group of files as always, but the new profile had the same symptoms as the old. I narrowed the origin of the corruption to the sessionstore.jsonlz4.


cor-el said

You can try to restore a recent upgrade.jsonlz4-<build_id> when available or use a utility to browse Windows System Restore points to see if you can find a recent sessionstore.jsonlz4 file. 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
Thanks for the valuable reminder. Would have save me a ton of time and trouble. However, I did a lot of relaunching that profile trying to figure out a way to fix it. According to your lesson, can I infer that would have resulted in the "good" backups being discarded in favor of the newer ones? If there's a next time, I'll immediately make a backup of the profile before I work on it

cor-el said

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).
I tried the troubleshooter with no success.

Modified by noel_envode

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Is there a way to sync sessions. Is that what syncing the history is for?

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If possible, can I either pay someone to do this for me, or at the very least walk me through it. There's a lot of information presented and I'm not at all comfortable doing this myself. I've already screwed things up enough. Based on what I'm reading, I'm afraid of doing more damage.

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You need to Sync "Open tabs" to sync the session data.


You can look at this tool to inspect a compressed jsonlz4 sessionstore file like files in the sessionstore-backups folder.

You can replace sessionCheckpoints.json in the profile folder with a sessionCheckpoints.json file that only contains "{}" (without the quotes) to get the about:sessionrestore page and select what to restore. Do not simply remove this file because that doesn't work (this is seen as a first start of a new profile).