Firefox Community Forum

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

Firefox won't open. System says it can't find VCRUNTIME140.DLL. There are SEVERAL copies on the drive. I believe I Refreshed and Reinstalled? And still cannot run.

This is the first time Firefox has failed in years. There are no instructions for this specific problem. FWIW I just installed AURA seemingly without problems.

Richard PS - Wouldn't it be great if the library of proven volunteer responses was searchable? r

I'm trying to install Firefox on my work computer (ARM64 version), but when I do I'm getting the crash report window at the end of the installation process (multiple times in a row), if I try to open the browser (only once), and during the uninstallation process (also multiple times in a row). I've tried a clean reinstall multiple times, including deleting the folders from program files, %APPDATA%, and all registry entries I could find (HKEY_CURRENT_USER>>SOFTWARE, HKEY_LOCAL_MACHINE>>SOFTWARE, HKEY_LOCAL_MACHINE>>SOFTWARE>>WOW6432Node).

I've contacted IT and they don't seem to think anything pre-installed should be affecting this. I'm unable to get a crash ID as I'm unable to even start the browser - all I get is the Firefox crash reporter, immediately. Is someone able to help me figure out why I can't get this working?

Whenever I close Firefox and try to reopen it, it brings up a system error that says, "The code execution cannot proceed because C:\WINDOWS\system32\pmls64.dll was not found. Reinstalling the program may fix this problem." I've tried completely deleting Firefox and reinstalling and it opens a new tab, but when I close it i get the same error message.

Firefox will not open on my MacBook Pro. Mac OS 15.5.

Terminal report: 2025-06-04 10:47:20.009 firefox[2076:19473] Server doesn't exist or doesn't provide correct selectors.

Behavior: Clicking Firefox to open results in a window asking for permission to install a new Helper tool. If I grant access I soon see a new window that says the Helper has been installed and I can go to my settings and manage it. Meanwhile the Firefox icon keeps jumping up and down and won't finish opening so I have had to force quit. If I do not grant access to the installation by clicking "cancel" I get the same result: Firefox dances and won't open. I have tried simple solutions like force quitting the dancing icon and restarting after getting the "installed" message. No difference. No difference also if I cancel the installation, force quit and restart.

Please help!

Getting the XPCOM can't load message. Uninstalled everything and reloaded firefox. I could not get it to work. Seems to be a lot of misinformation on the subject (irony here). Finally loaded the latest BETA test version problem solved ... for 2 days. Got the XPCOM message again. This time I reloaded the latest BETA test version and disabled updates. Pretty lousy solution but at least it has been trouble free for over a week. SHEEEZ!

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?

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:

Somehow the file ended up on my desktop. I think I saw it in a wierd place so I moved it out hoping it would go where it was supposed to go but it ended up on my desktop and now Firefox won't open correctly. Help?

Since upgraded to 138.0.1 my Firefox browser can't reopen after closing when multiple extensions are enabled. If run in safe mode or have all extensions disabled it can close and reopen correctly but when more extensions enabled firefox.exe will stay in background after closing and I can only reopen it after ending the process in task manager. It has never happened before.

Here attached all the extensions I have enabled.

Desde que he instalado Macos Sequoia 15.4.1, Firefox no consigue abrir ninguna ventana de internet. Internet funciona porque con Google Chrome o Safari sí que puedo navegar.