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Weird Nightly update made my Profile unusable

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I was running Firefox Nightly, opened about:profiles and launched a new instance with a different profile from there. At this time, the green update icon indicated there was an update in queue which was then installed right before starting the new Firefox instance, while the old instance was still running. At first everything was fine, my other profile launched, I did my work, closed it and after some more time also closed my main profile. But then when I restarted Nightly, it brought up a Mozilla Crash Report pretty much instantly... My profile is broken

I could work-around this by starting Firefox Beta which prompted me to Refresh the profile... Now I can launch Firefox again, but all the settings from about:config and my extension settings are gone. Is there any way to bring back those settings?

I made a backup of the profile before the refresh so I'm positive the data is still somewhere... However, just copying the profile.js file doesn't work, then I will get the prompt again to refresh my profile...

I was running Firefox Nightly, opened about:profiles and launched a new instance with a different profile from there. At this time, the green update icon indicated there was an update in queue which was then installed right before starting the new Firefox instance, while the old instance was still running. At first everything was fine, my other profile launched, I did my work, closed it and after some more time also closed my main profile. But then when I restarted Nightly, it brought up a Mozilla Crash Report pretty much instantly... My profile is broken I could work-around this by starting Firefox Beta which prompted me to Refresh the profile... Now I can launch Firefox again, but all the settings from about:config and my extension settings are gone. Is there any way to bring back those settings? I made a backup of the profile before the refresh so I'm positive the data is still somewhere... However, just copying the profile.js file doesn't work, then I will get the prompt again to refresh my profile...

Chosen solution

Okay, don't copy prefs.js, which has various custom settings and status data.

The places.sqlite file has history + bookmarks.

Tabs storage varies:

  • session data after a normal shutdown is in a file named sessionstore.jsonlz4 at the main level of your profile
  • session data after a crash is in the sessionstore-backups folder in a file named recovery.jsonlz4

You can use this tool to preview or save session URLs: https://www.jeffersonscher.com/ffu/scrounger.html

Extension settings may be in one or both of these folders:

  • [profile]\browser-extension-data
  • [profile]\storage
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All Replies (4)

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As a Windows user, I can't give you specific steps for doing things in a Linux profile. However, two thoughts:

(1) Can you start your regular profile in Firefox's Safe Mode?

See: Diagnose Firefox issues using Troubleshoot Mode

(2) Can you create a new profile, then migrate critical data files from your crashy profile to the new one to see how far you can get? For example, try places.sqlite first, test, then logins.json and key3.db/key4.db, test, then prefs.js, test.

See: Recover important data from an old profile

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(1) A refreshed profile yes, but not the one that got damaged.

(2) That's what I tried, but when I only copy prefs.js, it makes the refreshed profile crash. Luckily I don't have logins saved in Firefox, but what would be in places.sqlite? As I wrote above, extension settings would be important for me, as well as my opened tabs...

Thanks for trying though.

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Chosen Solution

Okay, don't copy prefs.js, which has various custom settings and status data.

The places.sqlite file has history + bookmarks.

Tabs storage varies:

  • session data after a normal shutdown is in a file named sessionstore.jsonlz4 at the main level of your profile
  • session data after a crash is in the sessionstore-backups folder in a file named recovery.jsonlz4

You can use this tool to preview or save session URLs: https://www.jeffersonscher.com/ffu/scrounger.html

Extension settings may be in one or both of these folders:

  • [profile]\browser-extension-data
  • [profile]\storage
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Sorry, those circumstances led me to oversee the real source of the crash: It was the gtk update (https://www.reddit.com/r/archlinux/comments/a5l38q/update_gtk3_made_firefox_crashed_when_set_option/) on Arch Linux together with browser.tabs.drawInTitlebar set to false. As soon as I set this setting to false in the prefs.js file, the profile works fine again.

Anyway, I migrated most of my extension settings by exporting them using their internal export functionality and will keep the files as backup. Your tool to recover my open tabs was also very usful as an instant life-saver, thanks for the fast help!