Firefox Community Forum

I am having Firefox crash on startup much like Firefox Desktop crashing on startup, initially in version 140, but I have downgraded to version 139 in my troubleshooting and I'm getting the same symptom.

It is frustrating that this does not seem to leave any records in the Windows event log or the Firefox crash reports, and that the fact that there's a known issue of this severity is rather hard to find.

export GDK_BACKEND=x11 MOZ_ENABLE_WAYLAND=0 MOZ_DISABLE_WAYLAND=1; /mnt/bootdrive/firefox3/firefox/firefox -P tx1p72s0.dev-edition-default XPCOMGlueLoad error for file /mnt/bootdrive/firefox3/firefox/libxul.so: /mnt/bootdrive/firefox3/firefox/libxul.so: undefined symbol: gdk_wayland_device_get_wl_seat Couldn't load XPCOM.

Has support for X11 been removed?

I am still using Win 7 but converting to Win 11. The most recent "patch Tuesday" update from MS killed Office 2016. Since then Fire Fox will occasionally pop up the "Couldn't load XPCOM." (no file extension) warning. It may do this when opened but not always. Can also occur in the midst of a session.

Program seems to be working correctly but some of my pinned locations disappeared when this started. New locations are retained between sessions. Is there a problem with continued operation with this warning? Is there something that I can do to repair it.

Howard Neuschaefer [email removed]@sbcglobal.net

Is there a way to make the URL high lighting of the domain more obvious? I find that most people can barely see the highlighting and I'd like to make it obvious (bolder and red, or highlighted in yellow, for instance.)

Can this be done via userchrome.css?

Thanks,

Thane

Firefox was working perfectly up until this morning and I'm pretty sure there wasn't a new update today. But now when I open the app a new window will briefly pop up for a fraction of a second and then disappear. Unfortunately this prevents me from accessing troubleshoot mode or crash reports so i can't provide much information on specifics.

I followed the steps here: https://support.mozilla.org/en-US/kb/firefox-keeps-crashing-startup and they haven't worked so far. I tried a clean install and restarting my computer multiple times, but no dice. There also don't seem to be any compatibility issues with the most recent version in the release notes.

I downloaded firefox and it worked for about a month. Now when I try to launch it, the screen flashes momentarily as though it were about to pop up, but then it does not actually open a browser window. I have uninstalled and reinstalled firefox more than once, I've tried a simple restart of the computer, and tried multiple different update methods (updated windows). Any suggestions?

I am trying to sign in , Firefox is my browser. message come on that firefox is running but it does not open. I close it once and again as the same sign comes uo telling me it is running and close the attempts.

Do I really NEED to swithc to another browser to avoid this?

PLEASE READ UNTIL THE END So, a few months ago I reinstalled Windows on my laptop because I had some bugs. After the OOBE was completed, I set it up and installed Chrome. However, when I tried to log in, the app suddenly force closed and could no longer be opened. So, I switched to Firefox. Everything was running fine. But now (06/26/2025), while I was using Firefox, it suddenly force closed (this is the first time it has force closed on me). I clicked twice on the desktop but it also didn't work, I'm confused about what to do, I absolutely don't want to use Microsoft Edge. When I tried to spam the Firefox icon on the taskbar while opening the task manager, crashhelper.exe suddenly appeared many times, I tried to delete those exe files but it had no effect, so I restored them back to their directory. I'm really confused whether my laptop is broken or if there's a bug in the Windows software? So that's it and thank you.

I originally deleted Firefox by accident and have downloaded it via Microsoft Store. All seems well then after I click on the app to open it, I Get the ‘Windows cannot find C:\Program Files\Mozilla Firefox\firefox.exe. Make sure you typed the name correctly, and try again’ for ‘Firefox’ error how can this be corrected?

Firefox has begun to instantly crash after opening. This occurs constantly, even though fresh installs, even if I run as administrator. It is the only application doing this, which is beyond weird. It seems to have begun happening after I opened a notepad file. Which seems ridiculous to me but that's when it initially crashed. If more information is required, please let me know, but I cannot even access say, crash logs.

Hello, today I could not launch Firefox on my Mac. Because this is a corporate machine from Kyndryl, I downloaded from Kyndryl App Store, I have rebooted the systems, I have updated iOS to last version, but still haven't solved the issue. This is the situation: Firefox is installed, I click to launch it, I am asked to authenticate with MFA I authenticate correctly, and Firefox just sits at the dock bar jumping, then stops jumping, and nothing else happens. I repeated the process several times, made several reboots, nothing changed. Can you suggest a solution?

Firefox will not update when I click the restart button. Firefox restarts but does not update. Closing Firefox manually (X) several times did not help. I had to restart my laptop and then Firefox updated. This started happening the update before 136.0.3, which is my current version. I don't want to keep restarting my laptop every time there is a Firefox update, which seems to be happening more frequently.

Lately every time I open Firefox on my PC (Win 10) it says that it is already running and that I need to close it first. How can that be if I just started the computer session?

The Firefox stable desktop taskbar shortcut issue unresolved for many months. Every time clicking on the Firefox taskbar/start shortcut is non responsive or it gives the error class not registered. Firefox nighly/developer do not have this issue. Fujitsu laptop, Widows 11 lates upgrades. Please fix.