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session restore a month out of date

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  • 1 has this problem
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  • Last reply by Ripley

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The last 2 times I've had to restart my laptop unexpectedly (ie not shut down properly), Firefox has loaded tabs from a month or so prior which means I lose recent tabs. Anything I can do to keep the automatic session restore more up to date? Couldn't find anything in settings that might apply.

The last 2 times I've had to restart my laptop unexpectedly (ie not shut down properly), Firefox has loaded tabs from a month or so prior which means I lose recent tabs. Anything I can do to keep the automatic session restore more up to date? Couldn't find anything in settings that might apply.

Chosen solution

Ripley said

recovery.baklz4 and recovery.jsonlz4 seem to be updating just fine in real time. I noticed current dates yesterday when looking around and they're current + updating now.

Sounds good. This points toward shutdown time as the more likely source of the problem.

If you check the main level of the profile folder, is there a sessionstore.jsonlz4 file there while Firefox is running? There shouldn't be; if there is one, it could be read-only/locked and preventing writing out the fresh file at shutdown. I would try to rename or delete it.

'The date of previous.jsonlz4 is December 19 2021, which is also the most current of the 3 upgrade.jsonlz4-build_id files. Should this be a more recent date?

Normally it would be the last date that you started Firefox, so that does seem rather out of date. As an experiment, could you right-click > Rename the file

previous.jsonlz4 => previousDEC19.jsonlz4

Then right-click > Copy recovery.jsonlz4 and right-click > Paste on a blank area of the list

Then you can right-click > Rename that one

recovery - Copy.jsonlz4 => previous.jsonlz4

If Firefox uses that file at the next startup, it would be another indication that there is an issue with saving the current session (or updating the session checkpoints) at shutdown.

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Hi Ripley, as a first step, could you observe whether Firefox is writing out your session history in real time? Here's where to check that:

Open the Troubleshooting Information page 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 there. This should launch Windows' File Explorer listing the contents of your current profile folder.

Double-click into the sessionstore-backups folder. There may be 3 files here or many:

  • recovery.jsonlz4: the windows and tabs in your currently live Firefox session -- does this have a current Last Modified date?
  • recovery.baklz4: a backup copy of recovery.jsonlz4 made at a lag of 15 seconds or so
  • 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 -- there may be several of these

You can keep this folder open and check in on it from time to time as you work.

Is recovery.jsonlz4 getting updated as expected?

If not:

We'll need to consider possible explanations for that, from a file lock problem to modified settings.

If it looks good:

When you close out of Firefox normally, Firefox removes the first two files from here and sets up a sessionstore.jsonlz4 file at the first level of your profile folder, and also updates the sessionCheckpoints.json file there. Something may be going wrong with those steps.

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Also make sure that you do not run Firefox in permanent Private Browsing mode (Always use Private Browsing mode; Never Remember History).

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Hi jscher2000, thanks for the very specific steps to follow.

recovery.baklz4 and recovery.jsonlz4 seem to be updating just fine in real time. I noticed current dates yesterday when looking around and they're current + updating now.

The date of previous.jsonlz4 is December 19 2021, which is also the most current of the 3 upgrade.jsonlz4-build_id files. Should this be a more recent date?

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Hi cor-el, I don't use Private Browsing often so probably not it, but thanks for another option to check.

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Chosen Solution

Ripley said

recovery.baklz4 and recovery.jsonlz4 seem to be updating just fine in real time. I noticed current dates yesterday when looking around and they're current + updating now.

Sounds good. This points toward shutdown time as the more likely source of the problem.

If you check the main level of the profile folder, is there a sessionstore.jsonlz4 file there while Firefox is running? There shouldn't be; if there is one, it could be read-only/locked and preventing writing out the fresh file at shutdown. I would try to rename or delete it.

'The date of previous.jsonlz4 is December 19 2021, which is also the most current of the 3 upgrade.jsonlz4-build_id files. Should this be a more recent date?

Normally it would be the last date that you started Firefox, so that does seem rather out of date. As an experiment, could you right-click > Rename the file

previous.jsonlz4 => previousDEC19.jsonlz4

Then right-click > Copy recovery.jsonlz4 and right-click > Paste on a blank area of the list

Then you can right-click > Rename that one

recovery - Copy.jsonlz4 => previous.jsonlz4

If Firefox uses that file at the next startup, it would be another indication that there is an issue with saving the current session (or updating the session checkpoints) at shutdown.

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jscher2000,

Assuming I looked in the right place, sessionstore.jsonlz4 was not there.

I followed your steps and restarted Firefox (which also updated, not sure if that's a factor) and it reloaded with all of my current tabs from this morning. I didn't 100% follow what this means (not a techy person!), so does this mean problem solved or just another clue along the way?

Also, to clarify: I can't remember the last time I deliberately restarted Firefox; maybe it was Dec. The last 2 times this problem has happened is because my laptop froze on the login screen and I had to shut it down by pressing and holding the start button. I'd assumed that Firefox creates an automatic backup every so often but perhaps I was mistaken.

I appreciate your time and expertise very much!

Modified by Ripley

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Firefox would normally copy sessionstore.jsonlz4 to previous.jsonlz4, so if there isn't a sessionstore.jsonlz4 or this file is stuck or Firefox failed to restore the session then that could explain why previous,jsonlz4 doesn't get updated.


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
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cor-el,

sessionstore.jsonlz4 doesn't seem to exist. I did a search in the ...Mozilla/Firefox folder and got no hits. If I understand you correctly, Firefox should be generating this file automatically?

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The sessionstore.jsonlz4 file will only be there when Firefox is closed and is copied to previous.jsonlz4 and removed after Firefox is started and is running.


You can create a new profile as a quick test to see if your current profile is causing the problem.

See "Creating a profile":

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

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cor-el,

Since I just re-started Firefox and it restored my recent tabs, will testing with a new profile turn up any issues now or should I wait to try this if I run into the same problem in the future?

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If it currently works and you see sessionstore.jsonlz4 with the correct timestamp after closing Firefox then there is no need to try a new profile.

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cor-el,

Looks like everything's a go for now. I'll bookmark this page in case the problem repeats itself.

Many thanks!