Firefox Community Forum

I'm getting the 'Firefox is already running, but is not responding. The old Firefox process must be closed to open a new window' message. I've gone to the task manager and end tasks. Then try to delete parent.lock in Firefox profiles in appdata. Then I get this message... The action can't be completed because the file is open in Firefox. Can you please help me with this problem.

When I try to run firefox 141.0 (Linux x64) I get:

libxul.so: undefined symbol: gdk_wayland_device_get_wl_seat Couldn't load XPCOM.

Is there a way to fix this?

I'm using Slackware 14.2.

I installed Firefox on my laptop, but I am not able to open the browser by double clicking the icon. Do not understand, why it is happening on my Dell laptop. Please suggest. Thanks.

Hello,

i was trying to check my apparmor stuff because of the warning on Linux. Now i tried duck.ai to instruct me , but created more damage than anything else. It said to set firefox in enforcement mode, now it wont start (well im using Firefox right now in complain mode)

How do I fix this problem that everything runs normally and safe?

Please help me! madmorph666@madmorph666-E14301:~$ sudo aa-complain /usr/bin/firefox /usr/bin/firefox wird in den Complain-Modus versetzt. madmorph666@madmorph666-E14301:~$ firefox ATTENTION: default value of option mesa_glthread overridden by environment. [Parent 72019, Main Thread] WARNING: gtk_widget_get_clipboard: assertion 'gtk_widget_has_screen (widget)' failed: 'glib warning', file /builds/worker/checkouts/gecko/toolkit/xre/nsSigHandlers.cpp:201

(firefox:72019): Gtk-CRITICAL **: 03:12:17.894: gtk_widget_get_clipboard: assertion 'gtk_widget_has_screen (widget)' failed [Parent 72019, Main Thread] WARNING: gtk_clipboard_request_contents: assertion 'clipboard != NULL' failed: 'glib warning', file /builds/worker/checkouts/gecko/toolkit/xre/nsSigHandlers.cpp:201

(firefox:72019): Gtk-CRITICAL **: 03:12:17.894: gtk_clipboard_request_contents: assertion 'clipboard != NULL' failed [Parent 72019, Main Thread] WARNING: gtk_widget_get_clipboard: assertion 'gtk_widget_has_screen (widget)' failed: 'glib warning', file /builds/worker/checkouts/gecko/toolkit/xre/nsSigHandlers.cpp:201

(firefox:72019): Gtk-CRITICAL **: 03:12:17.894: gtk_widget_get_clipboard: assertion 'gtk_widget_has_screen (widget)' failed [Parent 72019, Main Thread] WARNING: gtk_clipboard_request_contents: assertion 'clipboard != NULL' failed: 'glib warning', file /builds/worker/checkouts/gecko/toolkit/xre/nsSigHandlers.cpp:201

(firefox:72019): Gtk-CRITICAL **: 03:12:17.894: gtk_clipboard_request_contents: assertion 'clipboard != NULL' failed [Parent 72019, Main Thread] WARNING: gtk_widget_get_clipboard: assertion 'gtk_widget_has_screen (widget)' failed: 'glib warning', file /builds/worker/checkouts/gecko/toolkit/xre/nsSigHandlers.cpp:201

(firefox:72019): Gtk-CRITICAL **: 03:12:17.894: gtk_widget_get_clipboard: assertion 'gtk_widget_has_screen (widget)' failed [Parent 72019, Main Thread] WARNING: gtk_clipboard_request_contents: assertion 'clipboard != NULL' failed: 'glib warning', file /builds/worker/checkouts/gecko/toolkit/xre/nsSigHandlers.cpp:201

(firefox:72019): Gtk-CRITICAL **: 03:12:17.894: gtk_clipboard_request_contents: assertion 'clipboard != NULL' failed [Parent 72019, Main Thread] WARNING: gtk_widget_get_clipboard: assertion 'gtk_widget_has_screen (widget)' failed: 'glib warning', file /builds/worker/checkouts/gecko/toolkit/xre/nsSigHandlers.cpp:201

(firefox:72019): Gtk-CRITICAL **: 03:12:17.894: gtk_widget_get_clipboard: assertion 'gtk_widget_has_screen (widget)' failed [Parent 72019, Main Thread] WARNING: gtk_clipboard_request_contents: assertion 'clipboard != NULL' failed: 'glib warning', file /builds/worker/checkouts/gecko/toolkit/xre/nsSigHandlers.cpp:201

(firefox:72019): Gtk-CRITICAL **: 03:12:17.894: gtk_clipboard_request_contents: assertion 'clipboard != NULL' failed ATTENTION: default value of option mesa_glthread overridden by environment. ATTENTION: default value of option mesa_glthread overridden by environment. ATTENTION: default value of option mesa_glthread overridden by environment. ATTENTION: default value of option mesa_glthread overridden by environment. ATTENTION: default value of option mesa_glthread overridden by environment. ATTENTION: default value of option mesa_glthread overridden by environment. [Child 72430, Main Thread] WARNING: Unable to open /var/lib/flatpak/exports/share/dconf/profile/user: Keine Berechtigung: 'glib warning', file /builds/worker/checkouts/gecko/toolkit/xre/nsSigHandlers.cpp:201

(/usr/lib/firefox/firefox-bin:72430): dconf-WARNING **: 03:12:53.181: Unable to open /var/lib/flatpak/exports/share/dconf/profile/user: Keine Berechtigung ATTENTION: default value of option mesa_glthread overridden by environment. ATTENTION: default value of option mesa_glthread overridden by environment. ATTENTION: default value of option mesa_glthread overridden by environment. ATTENTION: default value of option mesa_glthread overridden by environment.

As title: after running updates, Firefox consistently crashes when launching.

To give more concrete details:

-Running on Linux, specifically KDE Fedora 42. Firefox was updated to 142 from 141, alongside various other updates. -When launching Firefox from any source (directly, through a link, through the terminal etc.), the only window that appears is the crash reporter. -This issue occurs when launching in safe mode. Removing and reinstalling Firefox, including deleting the entire .mozilla folder in Home at the same time does not resolve the issue. I am unable to test rolling Firefox back to 141. -When attempting to launch from the terminal (safe mode or otherwise), the following is output (personal info redacted):

restorecon: SELinux: Could not get canonical path for /home/[username]/.mozilla/firefox/*/gmp-widevinecdm/* restorecon: No such file or directory.

/usr/include/c++/15/array:210: constexpr std::array<_Tp, _Nm>::value_type& std::array<_Tp, _Nm>::operator[](size_type) [with _Tp = HeaderBarButtonType; long unsigned int _Nm = 3; reference = HeaderBarButtonType&; size_type = long unsigned int]: Assertion '__n < this->size()' failed.

Redirecting call to abort() to mozalloc_abort

[ExceptionHandler generates a minidump etc.]

Gtk-Message: [timestamp]: Failed to load module "appmenu-gtk-module"

(I would note that to the best of my knowledge I had not included a plugin for decoding widevine in my Firefox setup, and certainly the Firefox 141 instance on the device being used to write this post (same OS) does not include it) -The crash files in the .mozilla folder, meanwhile, consistently list a segfault at address 0x0.

Any advice on diagnosing/solving this issue would be greatly appreciated. Let me know if there's any other information that would be helpful.

If it would be more appropriate, I could report this through Mozilla's bugzilla instance, but given the issue seems to be very niche (Fedora's ABRT shows a total of 5 unique affected users in the last few days) I am unsure whether flagging this there would be appropriate.

Hello, I’m having trouble getting Firefox to work properly on my computer. During installation, the setup process becomes very slow, and once I manage to install it, Firefox hangs or becomes unresponsive within a few seconds after launching.

My system details:

Operating System: Windows 10 64-bit

What I’ve tried so far:

Reinstalling Firefox Running in Safe Mode Clearing profile data Disabling antivirus temporarily

None of these steps solved the problem. There are no specific error messages — the browser just freezes, and I have to close it via Task Manager.

I've used Firefox for years and have been very happy with it. Recently, however, it will not open no matter what I do. I've refreshed it, removed and reinstalled it, but it still will not open. What could be the problem?

Firefox will not open at all on atlasOS for windows 11. I have no clue why. The windows flash on screen, but don't leave an error or anything. I have tried troubleshooting mode. I have tried making another user. I have tried cleaning all Firefox registry entries and appdata files. I have tried refreshing Firefox. I have tried just about everything possible. I even tried using the Microsoft store version. Which suprisingly worked for around an hour before secombing to the same plague as the proper versions.