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When I "save and quit" Firefox 49, restart displays earlier tabs, NOT the set I was viewing on close.

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  • Last reply by adda

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I've been having some problems with FF acting strangely for a while. Sometimes when I "save (tabs) and quit", once FF exits, I get a "Firefox has crashed" box. Either way, when I restart Firefox, the open tabs are those I closed before exiting, NOT the set I tried to save. Basically, it saves the tabs that were open five minutes ago, NOT the ones open when I request to save.

Weird thing is the history displays the tabs that weren't "saved" for restart. Not the end of the world, but I use(d) FF because it has been reliable

I have setting to send crash reports in and the crashing has been happening for several months (usually when high resources being used, but again, AFTER FF seems to successfully shut down). I have tried restarting in safe mode without finding any problems. Everything is "up to date" and most plug-ins are set to "ask to activate". On Mint (Mate) 13

Also, my history and passwords all disappeared (set to save). Don't know that's "related" so it can be ignored, as I (think I) narrowed that to an update. Just adding it because it's happened more than once and FF crashes have increased, after apparently successfully exiting the program.

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Let's start with the five minute gap.

Interval Setting

By default, Firefox updates your session history file as often as every 15 seconds. You could test by starting a new session, and opening a tab to a different page every 15 seconds for a minute or two. Then quit Firefox and on your next startup, see how well it worked.

Note that this 15 second interval is a preference you could modify to be longer; some users concerned about heavy hard drive or solid state drive use might have done that. To check:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful.

(2) In the search box above the list, type or paste sess and pause while the list is filtered

(3) If the browser.sessionstore.interval preference is bolded and "user set", this value has been customized.

The default value of 15000 indicates 15000 milliseconds, which is 15 seconds. If you want to restore that value, right-click > Reset the preference. If you prefer a different value, you can double-click it to open an editing box. For example, 60 seconds would be 60000 (basically, the number of seconds followed by 3 extra zeroes); five minutes would be 300 seconds, so 300000 here.

Please research any session-related preferences in advance before editing to avoid breaking this feature.

Other session history files?

During your session, Firefox constantly updates a file named recovery.js in the sessionstore-backups folder of your currently active profile folder. If Firefox shut down normally (i.e., doesn't crash), that file is removed and its contents are placed in your profile folder (at the main level) under the name sessionstore.js -- since Firefox is crashing on you, I suspect this is not happening.

When Firefox starts up, it first look for sessionstore.js and if that isn't found, it looks for recovery.js. (There are other files; see https://dutherenverseauborddelatable.wordpress.com/2014/06/26/firefox-the-browser-that-has-your-backup/ for a detailed description of the design of this feature.)

One possible reason for a "gap" is if Firefox lost the ability to update recovery.js due to a file lock or other problem. In that case, it might have started a new file with a name like recovery-1.js. But usually this would not be so consistent, you would be rolling back much further than 5 minutes. Still, it's worth checking what else is in the sessionstore-backups folder. So...

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

  • "3-bar" menu button > "?" button > Troubleshooting Information
  • (menu bar) Help > Troubleshooting Information
  • type or paste about:support in the address bar and press Enter/Return

In the first table on the page, click the "Open Directory" button. Then after the file viewer displays, scroll down and double-click into the sessionstore-backups folder.

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

  • recovery.js: 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.bak: a backup copy of recovery.js
  • previous.js: the windows and tabs in your last Firefox session
  • upgrade.js-build_id: the windows and tabs in the Firefox session that was live at the time of your last update

Any mystery items here?

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Shutdown "crashes" occur when the shutdown process takes longer than an allowed period of time, which seems to be about 60 seconds. Rather than let Firefox linger hopelessly in memory, a watchdog process kills Firefox at that point.

(I typically get these when Firefox has reached over 2.5GB memory use and become sluggish or started giving display artifacts, and I attempt a normal shutdown. Most often on Facebook, not surprisingly, because of the endless scrolling consuming gobs of memory. Firefox apparently has trouble cleaning and detangling at that point.)

Your crash report data is analyzed for trends and possible fixes, but I'm not sure these are easy problems to solve (why Firefox sometimes hangs during shutdown), so they certainly still occur.


I'm not sure what you mean by this part:

I have tried restarting in safe mode without finding any problems. Everything is "up to date" and most plug-ins are set to "ask to activate".

What worked better in Safe Mode than in regular mode?

Note that Safe Mode disables extensions, not plugins, so you might take a look at those. Either:

  • Ctrl+Shift+a (Mac: Command+Shift+a)
  • "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Then cast a critical eye over the list on the right side. All extensions are optional. If in doubt, disable unnecessary or unknown extensions.

Often a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step.

Any improvement?

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Okay, I checked the browser.sessionstore.interval, which is set to the default (15000). It will take me a bit of time to reread and try the other suggestions.

I tried the safe mode start (previously) for the reason that I see that as a suggestion in troubleshooting. I don't have a lot of extensions, but had gotten some password ones because my saved ones seem to be disappearing when FF updates (that is my theory, having searched history, file dates, etc). The extensions don't help (if FF obliterates the passwords, they are GONE) so I'm just saving the logins.json and key3.db elsewhere. Going to delete those two extensions before more testing.

On the plugins, the only ones "activated" (always activate) are the OpenH264, Widevine Content Decryption Module and (currently) Shockwave Flash (it is now active after update, but had set to "ask before" before update.

I also noticed the "lock" file shows as "link (broken)". I don't remember it being "broken" in past and don't know if that affects anything? Just remembered when I went into the profile folder .

The sessionstore-backups folder has only the mentioned files; the upgrade.js file dated 10-13-2016, the others today (I just updated).

And yes, I tend to keep FF open a long time and memory usage builds up. Have been trying to exit before that point, but had still noticed the post exit crashes. Only other thing I notice that "might" (?) be pertinent in that regard is that often, it seems there has been a page with a repetitive "warning: non-responsive script" box and FF won't exit until I choose a response (I choose "stop script").

I will try the above suggestions and report back.