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Hi, I'm using the latest Firefox on a Windows 10 Dell laptop. Typically I have a lot of tabs open - 500+ sometimes. When I think this number of open tabs is getting absurdly large I do some housekeeping and close tabs individually that I do not currently need. Those I might want later I bookmark and then close. When I shutdown my computer I close Firefox first When I close Firefox I get the message "closing 5xx tabs". If there is an option I confirm. When I start my computer again, and then start Firefox, all of the previously open tabs are restored, which is awesome. Less awesome is that all the "housekeeping" individually closed tabs (which were not open when I shut down Firefox) are also restored. How do I prevent these individually closed tabs reopening while still having the tabs which were open at shutdown restored?

Thanks so much.

Hi, I'm using the latest Firefox on a Windows 10 Dell laptop. Typically I have a lot of tabs open - 500+ sometimes. When I think this number of open tabs is getting absurdly large I do some housekeeping and close tabs individually that I do not currently need. Those I might want later I bookmark and then close. When I shutdown my computer I close Firefox first When I close Firefox I get the message "closing 5xx tabs". If there is an option I confirm. When I start my computer again, and then start Firefox, all of the previously open tabs are restored, which is awesome. Less awesome is that all the "housekeeping" individually closed tabs (which were not open when I shut down Firefox) are also restored. How do I prevent these individually closed tabs reopening while still having the tabs which were open at shutdown restored? Thanks so much.

All Replies (8)

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What is the file size of your sessionstore files in the sessionstore-backups folder in the Firefox profile folder?

Updating session date for over 500 tabs can take some time, so if you cleanup the tabs and then immediately close Firefox then the session data stored in the profile folder (recovery.jsonlz4 in the sessionstore-backups folder) may not have been updated and still has the recently closed tabs listed as open and sessionstore.jsonlz4 also gets those tabs. You can try to wait longer before closing Firefox and possibly observe the timestamp of recovery files in the sessionstore-backups folder to see how long it takes before they settle.

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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Hi Cor-el,

Thank you very much. The screenshot image shows the contents on my sessionstore-backups folder.

I do not immediately close Firefox after doing some clean up.

You clearly know 1000% more than I do about Firefox so hopefully the screenshot gives you some answers to your questions - whether a file is large or small..

I much appreciate your time and expertise.

Best regards

John

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The compressed sessionstore file are about 4 MB and uncompressed could be about 40 MB, so this is rather high. Those files usually get updated in idle time in the background. 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 and restore the session stored in this file.

  • 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.

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Hi Cor-el,

Thank you again, very much.

Understanding what you have said I will check in the morning after my computer was in sleep mode all night to see when the last version of recovery.jsonlz4 was written. This will probably be when my computer was most idle. I guess the best thing for me to do is simply to avoid leaving tabs open. I do it as a memo of things I need to revisit, but apparently creating a large sessionstore file(s) is detrimental to managing my tabs and lets them get out of hand.

I appreciate your help.

Aloha

John

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Hi Cor-el,

Thank you again for your generous help. Your expertise gave me some insight into the working of Firefox in this regard.

Based on what you said I discovered a few things: 1. Firefox did not apparently update the sessionstore-backupss folder items during "sleep" mode of my computer. 2. I did not do any renaming or anything really. I just monitored, and continue to monitor, the sessionstore-backups folder items. 3. I did allow some time to elapse before shutting down Firefox after individually closing various tabs individually. 4. I only closed a few tabs this way. 5. Without any action on my part the "recovery.jsonlz4" and "recovery.baklz4" and "previous.jsonlz4" started updating to a current "date modified" time stamp. Previously the "previous" file had remained showing 2/5/23. 6. The above date modified updating seems to occur in runtime or during Firefox shutdown or during start up of Firefox. This does not seem to take any appreciable time. For example as I was typing this "recovery" files have updated from 7:21am to 7:22am to 7:23am. 7. Individually closed tabs are now not reopened after Firefox shutdown and restart. 8. The size of the sessionstore-backups files now deceases as I close tabs. 9. I didn't do anything, reset anything, rename or move anything, or get any Firefox updates - except perhaps exercise a little more patience in shutting down - as you first suggested. So I'm a little mystified as to why things started working properly. But I'll take it! 10. This is an old laptop, subject to a lot of abuse, does not always boot cleanly, so I'll assume that may have something to do with it. 11. I'm now much more conscious of tab management and its possible ramifications thanks to you. 12. I still have about 500 tabs open but this does not appear to degrade performance.

Have a great day, and thanks again.

John

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Hi Cor-el, Just a further brief update for anyone who might read these posts. Thank you again for your help. The "recovery" files in the "sessionstore-backups" folder update frequently in run time. This stops happening if Firefox starts to use "too much" memory and "hangs" in some way. The "solution" to this appears to be restarting the computer. Closely monitoring this and not closing individual tabs while Firefox is "hung" solves the issue of these closed tabs reopening using an older "recovery" file. John

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You can try the button on the about:memory page to free up memory.

You can check the about:memory and about:processes pages for info about all processes. See also the about:unloads page for info about the tabs.

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Hi Cor-el,

Thanks. The results of selecting reports are way over my head. As long as Firefox works I'm fine  ;-) Have a great day.

John