Firefox コミュニティフォーラム

My copy of Firefox, installed on a MacBook Air, has suddenly decided not to open. When I click the icon I see a brief flicker on the screen but the application does not open. Version is 140.0.4. Has anyone else experienced this?

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?

Hello,

I have the latest version (140) of Firefox installed on a Windows 11 laptop with the latest Windows updates. It works fine for my user (who, BTW, has admin privileges) but it won't even start for my wife's Windows user. To be precise, "won't start" means that when you try to launch it it sometimes looks like it's trying to create a window but immediately closes it with no error messages, no crash reports, no logs, nothing at all. It won't even start from the Run menu with any command line flag like -p, -ProfileManager or even -safe-mode, I tried all of them.

Other things I've tried: 1) Check the Windows event logs. Nothing. 2) Run sfc /scannow to check for corrupt system files. 3) Uninstall Firefox, delete the Program Files\Mozilla Firefox folder, and re-install it. 4) Move the entire Firefox folder inside %appdata% to a temporary folder outside users. Firefox recreates it, creates 2 new profiles and dies silently again! 5) ...and a lot of other things that I read online and do not remember anymore.

At this point I'm at a loss and I'm an IT guy. Of course I have no idea how this happened, the browser used to work fine up until a week ago or so. Other software that might interfere is Malwarebytes, but it works fine for my user, so... 🤷🏻‍♂️

Thanks in advance for any ideas.

Hi, The browser suddenly closed, and I can't open it since then. I searched for what to do but couldn't find anything helpful. I tried reinstalling Firefox, but it still doesn't work. I don't know it is a helpful information, but the other browsers (like Chrome and Opera) also don't open.

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.

Firefox is my default browser. I few days ago, it failed to open, and continues to do so. When I click on the icon, I get the blue spinning circle for a few seconds, then nothing. I have tried to refresh and reinstall, but nothing worked.

Firefox keeps crashing, or better doesnt even open. In Task Maneger on my Windows 11 System I didnt even see the task preformed. So I tried to uninstall Firefox and reinstall Firefox, still the same Problem. I tried to refresh Firefox but it was no use. Sometimes for a brief moment of time a small window opens with the Firefox logo, for two seconds I can read the word Firefox Troubleshoot but it closes instantly. I need Firefox as my Browser and would like to have it back in use as soon as possible. Thank you for your help LH

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.

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?

Ive uninstalled it multiple times, done just about everything suggested online, and even got it working for a bit off the Microsoft store. But for some reason, my desktop Firefox will not open at all.