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Restore Previous Session not working - or, not properly at least

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OK, I was using a very old version of firefox previously and restore previous session worked perfectly. If my computer crashed, when I rebooted it, the "trouble finding pages" message came up, click to restore session, and everything came back.

Then.... I upgraded to version 72.0.2 (64 bit)

Session restore no longer works, or at least not the way it should be working.

If I had say 20 windows open when the computer crashed, when I finish a reboot and start Firefox, I get the "trouble finding pages" message, and I click to restore session as before.

Anywhere from 2 to maybe 5 windows will restore. The rest are gone.

I suspect it has to do with the fact that there were now multiple "instances" of firefox running in the task manager, and what's happening is that it's restoring the windows in ONE of those previous instances, but not all of them.

It gives me the impression that the session restore function isn't tracking all the windows open in all those separate instances, but rather it's only tracking one instance.


Any assistance would be appreciated.

OK, I was using a very old version of firefox previously and restore previous session worked perfectly. If my computer crashed, when I rebooted it, the "trouble finding pages" message came up, click to restore session, and everything came back. Then.... I upgraded to version 72.0.2 (64 bit) Session restore no longer works, or at least not the way it should be working. If I had say 20 windows open when the computer crashed, when I finish a reboot and start Firefox, I get the "trouble finding pages" message, and I click to restore session as before. Anywhere from 2 to maybe 5 windows will restore. The rest are gone. I suspect it has to do with the fact that there were now multiple "instances" of firefox running in the task manager, and what's happening is that it's restoring the windows in ONE of those previous instances, but not all of them. It gives me the impression that the session restore function isn't tracking all the windows open in all those separate instances, but rather it's only tracking one instance. Any assistance would be appreciated.

All Replies (4)

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Firefox is a multi-process application, but your session file is written and read by a global process and the individual web content processes are for rendering tab contents.

Are there any additional windows available to re-open if you check any of these:

  • "3-bar" menu button > Library > History > Recently Closed Windows
  • "Library" toolbar button > History > Recently Closed Windows
  • (menu bar) History > Recently Closed Windows

If so, are the windows that were open at the time of the crash, or already closed at the time of the crash?


It's not clear what is going wrong with your Firefox. During the first startup after a crash, Firefox should restore the last readable session history file, which should be from shortly before the crash. Possibly the crash corrupted that file and Firefox restored an older one, or possibly the file wasn't being kept up-to-date.

Couple questions:

  • Was this on the first run after your update?
  • Did you modify the browser.sessionstore.max_resumed_crashes preference to zero? Normally, it has a value of 1, meaning that Firefox will try one automatic restore before showing the screen indicating there is a problem restoring your previous session windows and tabs. (With a value of 0, Firefox skips directly to that screen.)

Do you want to check other session history files for possible additional windows/tabs? Firefox creates numerous session history files, but because session history is only for the immediately previous session, you would need to check ASAP.

Start by making a backup of your existing session history files. Here's how:

You can open your current Firefox settings (AKA Firefox profile) folder using either

  • "3-bar" menu button > "?" Help > Troubleshooting Information
  • (menu bar) Help > 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.

In your profile folder, double-click into the sessionstore-backups folder. Save all files here to a safe location such as your Documents folder.

It's also useful to check this folder from time to time during your session to see whether recovery.jsonlz4 has stopped updating. That could indicate another problem.

The kinds of files you may find among your sessionstore files are:

  • recovery.jsonlz4: the windows and tabs in your currently live Firefox session (or, if Firefox crashed at the last shutdown and is still closed, your last session)
  • recovery.baklz4: a backup copy of recovery.jsonlz4
  • 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

Could you take a look at what you have and the date/time of the various files to see whether you think any of them would have the missing tabs?

To preview the contents of a file, you can drag and drop it onto a tool on my site, then click Scrounge URLs:

https://www.jeffersonscher.com/ffu/scrounger.html

If you don't get a list within 15 seconds, that probably means the script is caught in a loop. You may need to close the tab to avoid a tab crash and then try again in a new tab.

If you get a useful list, use the Save List button to archive it as a web page of clickable links for future reference, in case no other approach is successful.

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Of course, the current version of Firefox is 86.0.1, and the current Extended Support Release is based on Firefox 78. Any particular reason you are not updating?

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I don't think the version number should matter.

Any version I've tried after it became impossible to turn off Multi-process, does this.

I might have 20 windows open, I right click Firefox in the taskbar, and select "Close All windows".

IF it closes all windows, when I restart Firefox I'm only able to get back maybe 5 of the windows that were previously open.

Frequently, when I do the "close all windows" it only closes some of them. Not all of them. So I have to "close all windows" several times to finally shut down Firefox.

Then when I restart it, the only windows that will/can reopen, is the very last "instance" of Firefox that was running in the task manager.

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Magelord said

I might have 20 windows open, I right click Firefox in the taskbar, and select "Close All windows". IF it closes all windows, when I restart Firefox I'm only able to get back maybe 5 of the windows that were previously open.

If you want to be able to access all of those windows in your next session, do not use that method to close them. That method closes them sequentially and by default, Firefox only remember the last 3 closed windows. Instead, exit Firefox using the menu, either:

  • menu button > Exit
  • (menu bar) File > Exit

Using Exit causes all of those windows to be open windows when you restore your previous session.