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Firefox crashes

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Firefox crashes on startup immediately after very briefly displaying the screen to recover from a previous crashing. This was preceded by a dozen or so crashes while viewing YouTube videos. Other profiles continue to work, but my with main profile Firefox cannot start.

Firefox crashes on startup immediately after very briefly displaying the screen to recover from a previous crashing. This was preceded by a dozen or so crashes while viewing YouTube videos. Other profiles continue to work, but my with main profile Firefox cannot start.

Chosen solution

hi, please reset the network.trr.mode preference in about:config back to "0" - dns over https is not supported in firefox 60 yet and leads to the crashes you've referenced.

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All Replies (9)

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MOZ_CRASH Reason MOZ_RELEASE_ASSERT(mWorkerThread == GetCurrentVirtualThread()) (not on worker thread!)

Crash Reason EXCEPTION_BREAKPOINT Version 60.0.1

Known Bug was suppose to be fixed in 60.0.1


Crappy Firetitle Extension Can you try is Safe Mode please : Try Firefox Safe Mode to see if the problem goes away. Firefox Safe Mode is a troubleshooting mode that temporarily turns off hardware acceleration, resets some settings, and disables add-ons (extensions and themes).

If Firefox is open, you can restart in Firefox Safe Mode from the Help menu:

  • Click the menu button New Fx Menu, click Help Help-29 and select Restart with Add-ons Disabled.

If Firefox is not running, you can start Firefox in Safe Mode as follows:

  • On Windows: Hold the Shift key when you open the Firefox desktop or Start menu shortcut.
  • On Mac: Hold the option key while starting Firefox.
  • On Linux: Quit Firefox, go to your Terminal and run firefox -safe-mode
    (you may need to specify the Firefox installation path e.g. /usr/lib/firefox)

When the Firefox Safe Mode window appears, select "Start in Safe Mode".

SafeMode-Fx35

If the issue is not present in Firefox Safe Mode, your problem is probably caused by an extension, theme, or hardware acceleration. Please follow the steps in the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article to find the cause.

To exit Firefox Safe Mode, just close Firefox and wait a few seconds before opening Firefox for normal use again.

When you figure out what's causing your issues, please let us know. It might help others with the same problem.

Modified by Shadow110

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I apologize for omitting this detail, but this is happening in safe-mode.

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Hi, this was suppose to be fixed in this version your on as far as I can tell.

Please try this : uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files , C:\Program Files(x86) & C:\ProgramData Then restart system. Then run Windows Disk Cleanup. (Note: This should be Pinned and run Weekly, If never done below expect 10's of gig's) Then run it again and click the button that says Cleanup System Files. Note: your Firefox Profile is saved. But you should make a back up before you do :

Reinstall with Current Release Firefox 60.0.1 with a Full Version Installer

Please let us know if this solved your issue or if need further assistance.

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Chosen Solution

hi, please reset the network.trr.mode preference in about:config back to "0" - dns over https is not supported in firefox 60 yet and leads to the crashes you've referenced.

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philipp said

hi, please reset the network.trr.mode preference in about:config back to "0" - dns over https is not supported in firefox 60 yet and leads to the crashes you've referenced.

How do I get to that if even safe mode crashes before I can do anything? (Noting, BTW, that I enabled at the request of Mozilla a few days ago.)

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Try to start Firefox with the about:blank page by creating a copy of the current Firefox desktop shortcut. Add a space and -url "about:blank" to the target field in the Properties.

That way you can prevent opening tabs and can modify the above mentioned pref more easily.

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hm, not sure how mozilla has requested that you toggle the pref... if you're not getting firefox to open at all, you'd have to go into the profile folder and manually edit the prefs.js file by removing the line referencing the network.trr.mode pref.

Profiles - Where Firefox stores your bookmarks, passwords and other user data

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philipp said

hm, not sure how mozilla has requested that you toggle the pref... if you're not getting firefox to open at all, you'd have to go into the profile folder and manually edit the prefs.js file by removing the line referencing the network.trr.mode pref. Profiles - Where Firefox stores your bookmarks, passwords and other user data

Most recent Mozilla newsletter, IIRC. Resetting the preference back to 0 has allowed me back into the profile.

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Thank you everyone for your prompt, and accurate help.