Forum der Gemeinschaft Firefox

I have this message after returning from nightly version to the stable one: ``` Using an older version of Firefox can corrupt bookmarks and browsing history already saved to an existing Firefox profile. To protect your information, create a new profile for this installation of Firefox. ```

Summary - Firefox crashes repeatedly. yesterday, I decided to switch to Firefox after using Chrome for a while. it worked fine and I synced my data from Chrome. today, at some point I noticed Firefox is no longer open in my taskbar. I decided to reopen it - it crashed. since that moment it has never worked again. I tried launching it in safe mode (firefox.exe -safe-mode), didn't work. tried reinstalling it, didn't work. manually deleted the files from C:\Program Files and AppData, installed Firefox again, didn't work. reinstalled gpu drivers, didn't work. sfc /scannow-ed, you guessed it - still crashes. what else could I possibly try? please help.

os: Windows 11 Home Firefox source: https://www.mozilla.org/en-US/firefox/all/desktop-release/win64/

p.s. this was posted through an android phone but the problem only occurs on windows

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.

I know that this is not a new issue, but it's a recurrent issue that keeps coming back. When I install a Firefox update, MacOS (15.5 at present) often gives me a popup that says "Firefox is trying to install a new helper tool. Enter your password to allow this."

But I don't ever want to enter my password to install a tool that doesn't identify itself. I view Firefox as always being at the forefront of security, but asking for a password for a tool that's not identified is a security risk. Maybe it's MacOS that refuses to identify the "helper tool", but it's a Firefox problem. It's unacceptable.

In today's update, Firefox won't work at all after I hit cancel to the password dialog. I have to Force Quit it. I'm going to have to delete Firefox and reinstall, and hopefully that will work. But I shouldn't have to do this. It's unacceptable that this keeps happening. (If there's some weird configuration issue at my end, I think Firefox should be flexible enough to deal with it.)

I don't know what version of Firefox is generating the problem, because it's currently unresponsive, since I haven't entered my password to install the helper tool. (I'm writing this in Safari.)

(In the attached image, I blotted out my username.)

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?

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

Hi, I just want to tell the support that new version, 144.0 on 9th October 2025, has some glitch on my HP Chromebook 11 G5 EE. It will auto close when I try to open the Mozilla browser. So, I have to uninstall 144.0 and install 143.0 version which does not have issue auto close on my chromebook. Please look into this. Thanks.

When I first open Firefox from the icon in my taskbar the opening window says the following:

'Unable to connect Firefox can’t establish a connection to the server at 0.0.0.4. The site could be temporarily unavailable or too busy. Try again in a few moments. If you are unable to load any pages, check your computer’s network connection. If your computer or network is protected by a firewall or proxy, make sure that Firefox is permitted to access the web.'

However this is only the first window, after that I can open a new tab in the same window without any problems.

I have uninstalled and reinstalled Firefox without avail. Can anyone help please?

- Had 3 windows open with numerous tabs and tab groups - Firefox sync was enabled, as well as a 2-3 plugins AFAIK - Version installed is latest as of this writing 139.0.4 - Initial crash caused by opening and quickly closing (IF that succeeded before crash) a onedrive share link - Cannot start firefox any more, also not in safe mode - the only thing that works is launching it with a fresh profile.

The report ID is bp-a8c824fc-a7fb-4290-a72b-b63160250620

Ideally I can resolve this without needing to refresh or start over with a new profile

After upgrading to version 144 in Windows 11, the portable version of firefox stopped opening, the splash screen appears and shuts down. If you run firefox.exe, it works, but the portable program itself crashes and won't start. There is nothing in the logs, antivirus is off, windows security is turned off. How to fix this?

After installing Firefox on a new Windows 11 computer, when I click on the Desktop icon, a Firefox window opens but it doesn't open previous Tabs and the Application menus does not work. I can open new Tabs though and it downloads websites. If I click on the Firefox icon on the Windows Taskbar, Firefox operates normally.

Why doesn't the Desktop icon start Firefox so it works correctly?

Thanks

Wayne Carpenter

Hello,

Recently, (past month or so) I have had difficulty opening Firefox on my PC. Found suggestion of renaming the .exe which did work, but now it will not open AT ALL. Uninstalled, and re-installed. nothing. Renamed .exe. Nothing. It will OPEN as admin, but cannot access any settings or browse. I am at a loss, and really do not want to go back to Chrome.

Previously attempted uninstalling ESET antivirus and Defender, and still would not open.

Thank you!

-Tim

When trying to launch the browser from a network folder, I encounter the errors shown in the screenshots. If I launch the browser on one computer, everything is ok, but if I need to launch it on at least the second one, I encounter this error until I close the browser on the first one. I don’t know what could have happened, because I didn’t touch the configuration and everything worked fine for us last year. Nothing was updated or changed. Firefox Portable ini file configuration:

I use translation A LOT. (I'm learning a foreign language.) It would help to be able to move or resize the results window. Right now, it covers the original foreign language text. I want to compare the translation with the original text and the fixed size and position of your results window makes that a lot more difficult.

There always seem to be daily issues, "Mozilla Not Responding". We clear out Cookies, Cache, history, etc. throughout the day. We've had to shut it down and restart the computer. Oftentimes, the system just shuts down.

For the last few weeks, we have an unknown popup from Mozilla, "Unable to load XP.com". Not sure what this may be or why this popup suddenly started. We close it and pops up periodically several times in a day. I am attaching a screenshot of the image.

Thanks