Firefox Community Forum

Through extensive troubleshooting, I am unable to get firefox to open at all.

I've done a full uninstall, cleaned all user directories, program files / x86, program data, appdata roaming and local, etc. I used the Microsoft uninstaller and even Revo Uninstaller to remove everything related to Firefox, did a restart and reinstall of the latest one and it still won't launch.

Firefox was previously working until a reboot occurred and now it won't launch.

Firefox 32 bit seems to work when installed, and running Firefox as an admin previously worked but no it no longer does.

I looked at the following articles: - https://support.mozilla.org/en-US/kb/firefox-wont-start-find-solutions - https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles - https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles#w_start-the-profile-manager-when-firefox-is-closed

There's no malware on this machine (business EDR on it, even disabled it as a test and it still didn't open).

I was able to launch the profile manager but now I am unable to as the processes launch in task manager and then within 5 seconds they close.

Firefox is not running in the background for any user (I'm the only one logged in after a reboot as well)

I'm unable to open in troubleshoot mode either. Tried run as and admin cmd "C:\Program Files\Mozilla Firefox\firefox.exe" -safe-mode

Ran SFC / scannow / DISM restore health commands as well and both came back fine / no integrity violations

Firefox 146.0.1 crashes every time upon launch (basically fails to launch), even in troubleshooting mode, with exception code 0xc0000005. Prior to today, it was working fine. Windows does not show any updates made over the last couple of days. I am on Windows 11 25H2, and I'm current with updates. Chrome works. Edge works. I logged on to the same computer as a different user (different profile folder in the user AppData folder) and Firefox still does not work. I tried to refresh Firefox and that did not resolve the issue. I tried to uninstall and reinstall Firefox and that did not resolve the issue. I tried to run DISM and SCANNOW and that did not resolve the issue. No issues are detected with a virus scan. I am stumped - please help!

Hello! I am an avid user of firefox (especially with adblockers) on a windows 11 PC. Unfortunately, I have recently been experiencing an issue where when I attempt to open firefox, a window will open for a split second before instantly closing again. My PC is up to date, I have tried refreshing firefox and doing a clean install, but cannot seem to overcome the issue, or even open it in safe mode. Does anyone have any advice? Many thanks in advance!

Hello, When I went to launch Firefox after starting up my PC this morning, I was greeted with: "Your Firefox profile cannot be loaded. It may be missing or inaccessible".

I went right to the Mozilla forums and found the help page [https://support.mozilla.org/en-US/kb/how-run-firefox-when-profile-missing...] . In this article it detailed how I should go into my AppData, then Mozilla, then Firefox, and look to see where my profile.ini file is. My profile.ini file was there, alongside the installs.ini and a few other folders. I attempted also to launch the profile manager using run and the "firefox.exe -P" command, but I got the same profile error as when I tried launching the app. The help page then recommended deleting the profile.ini file and then launching Firefox to hopefully remake the default profiles.ini file and enable me to launch Firefox, so I attempted that. When I tried relaunching Firefox, the profiles.ini file did not re-appear in my Firefox folder.

I then tried deleting the Firefox folder itself, and relaunching Firefox. This resulted in it being remade, but with just 2 folders left: Crash Reports and Pending Pings. Obviously that's not ideal, so I right clicked the Firefox folder and used the Windows "Previous versions" feature to restore the Firefox folder to a backup of how it was this morning. I then re-tried launching and I still got the same missing profiles error message. I also briefly attempted manually making a new profiles.ini file with notepad, and pointing it towards my Profile withing my Profiles folder, but that still resulted in the same missing profiles error.

This is basically where I am at now. I have confirmed that I do in fact see my actual profile in my "C:\Users\****\AppData\Roaming\Mozilla\Firefox\Profiles" folder, and as far as I can tell my profiles.ini file correctly points towards it. I did another reset of my Firefox folder to a backup of where I was at this morning before attempting anything. I can confirm my Windows account (Admin, and only account on the computer) has full read and write access to all Folders and files within the Mozilla folder, although I will mention some of the files in the Firefox folder were marked with the "Read-Only" attribute (not sure if that matters, but I tried unchecking those and still no luck)

As far as I can tell I have thoroughly exhausted all the easily accessible tips on the internet for solving this, so I am wondering what to try next?

TLDR: Error: Your Firefox profile cannot be loaded. It may be missing or inaccessible" Already Attempted (And failed): -deleting and prompting a remake of the profiles.ini folder -using firefox.exe -P to launch Profile manager -deleting Firefox folder to prompt a remake of that -multiple uninstalls and reinstalls of Firefox -manually remaking profiles.ini file after it didn't come back after deletion

Will link images of (1) profiles.ini file. (2) Profiles folder.

Firefox keeps crashing on my laptop I've had it run very successfully on the same laptop the first time i installed it it crashed the same way it does now but one day it randomly worked and continued working for about 9 months however at some point it crashed and i deleted it and reinstalled many times at best i have downloaded it and have managed it to run for about 10 minutes then closed and failed to load properly now it fails to launch completely at worst it doesnt run at all .i have tryed downloading it from the microstoft store and your website this time i downloaded it from Microsoft please help!

I’m suddenly unable to open Mozilla Firefox at all on my Windows 11 Pro (version 25H2) Surface Laptop. The browser never launches - every attempt immediately crashes and opens the Firefox Crash Reporter.

I tried uninstalling and reinstalling a fresh copy of Firefox (and removing the old application files, though the original Firefox program folder has 13 .tmp files inside a “tobedeleted” folder that I can’t delete), but the issue persists. When I try to install or uninstall Firefox, I get the same behavior: Firefox never opens, and I end up with multiple instances of the Crash Reporter popping up instantly.

Tried renaming firefox.exe as well to no avail. Chrome and Edge are working fine.

I had been using the Mozilla Firefox VPN for a few weeks, but now it will not launch. I sign in without a problem but when I click on the VPN icon on the toolbar, nothing happens. I just get the pop-up to try the VPN and "Get Started" (see attachment).

Please advise.

Hello,

I am looking for help with a Windows 11 Pro 24H2 system. Firefox no longer works despite a clean uninstall and reinstall, including deleting all related folders.

When I reinstall Firefox, the error appears, but the application still manages to launch. However, after a system restart, the issue comes back.

When launching Firefox, I get the following message: “Firefox.exe failed to start correctly (error 0xC0000022).”

I can’t find any recent information about this issue. Thank you in advance for your help.

After my pc has been on for a while, seemingly random duration, Im not able to open firefox anymore. For example if clicking on a link in discord, or if I close the browser and want to open it again. I've tried refreshing and reinstalling but that didn't help.

I cannot get into Firefox due to an error message that keeps coming up. Your Firefox profile cannot be loaded. It may be missing or inaccessible.

I have tried deleting and reinstalling it, but it didn't really uninstall completely. I have tried a few suggestions from online, which didn't work. I also tried right clicking on the Firefox symbol and went into some of the different options, but nothing worked for me.

When I open Firefox in Windows 11 a small window appears that reads, "Firefox Couldn't load XPCOM. I have not found any solutions to stop this that work. Will Mozilla fix this?

Tonight I received a notice that a new version of Firefox was available and asking if I wanted to download it. It showed me the new Kit mascot so I decided to let it install. It seemed to install normally but when it tried to open what I guess is a welcome/new features page, it crashes, and just showed a prompt to try again. This continued in an endless loop and I had to shut it down. Unfortunately I no longer had a functioning version available that I could find so I downoaded the ESR version to be safe (ver 140.5.0esr) which I am now using. Somehow I was able to recover bookmarks and hopefully other saved info. Can anyone advise what has happened? I have used Firefox for many years and never had this sort of problem before. Running Windows 11 on a new Dell i7 PC.

I got so frustrated with not being able to reinstall Firefox because I kept getting the error message "Your Firefox profile cannot be loaded. It may be missing or inaccessible". So I deleted all the profiles after copying them to an external hard drive. Then I copied the file ending in.test from the Old Firefox data folder on my desktop to the AppData/Roaming/Mozilla/Firefox/ profile. Then I copied the biggest file ending in .default from the backed up Local profiles to the AppData/Local/Mozilla/Firefox/ profile. It doesn't matter if I delete or keep the Old Firefox data folder on my desktop, I still get the Profile Missing error message. What can I do, so my laptop would appear as if it had been powered up straight out of the box and never had Firefox initially installed or what do I do with my profiles to make them accessible?

Hello! Thank you for taking the request!

My firefox browser crashes repeatedly at startup, only showing the crash report window instead of opening the browser. When starting the browser using troubleshoot mode, it crashes too, showing the same result. After uninstalling and re-enstalling the latest version, the exact same problem continues.

I've scanned for viruses and checked the computer RAM and neither seems to be the problem.

The latest submitted crash report ID is bp-0917ab7e-e656-42ff-aa92-40b8c0251112

I'm really grateful for your help, and looking forward to your reply!

My Surface Laptop 7 w/ SnapDragon Elite's Firefox installation started crashing this morning immediately after rebooting to complete some Windows updates. I have attempted starting Firefox in Maintenance mode, Uninstalled and reinstalled and I still get the crash reporter. Refreshing Firefox at the uninstall process does not fix it.

I'm running Windows 11 Enterprise edition, fully patched w/ Firefox 146.0.

The 4 Windows updates that were installed:

Uninstalled KB5072033 Uninstalled KB5070311 Cannot be uninstalled KB5072641 Cannot be uninstalled KB5071142

Still didn't fix the problem.

These are the recent crash reports:

Crash ID: bp-8ec5b63c-4408-437c-b9bb-f4d5b0251213 Crash ID: bp-ce396463-0a75-46b6-8131-33cce0251213 Crash ID: bp-ea0b59dd-1cee-48da-957e-949120251213 Crash ID: bp-f9342e01-1a55-4387-af6d-3b8ef0251213

Any help is appreciated!

Hi, after clicking FF icon, I got nothing. Profile manager (firefox.exe -P) does not start. In event viewer there is log: Name of the application causing the error: firefox.exe, version: 147.0.0.11, timestamp: 0x695c3722 Name of the module causing the error: unknown, version: 0.0.0.0, timestamp: 0x00000000 Exception code: 0xc0000005 Fault offset: 0x00007ffc561c6160 Faulting process ID: 0x4A54 Startup time of the application causing the error: 0x1DC85EE68CB3BAD Faulting application path: C:\Program Files\Mozilla Firefox\firefox.exe Faulting module path: unknown Report Id: e599c553-d77c-4b73-a863-1ccaa8d3bd4c Faulting full package name: Faulting relative application ID for package:

Last time deleting profile was helpfull, today nothing helps... Reinstall - the same... Any ideas?

After the latest version was updated, Version 149.00.7, on my laptop, on 27 March 2026, the browser closed midway while I was working, and now I can no longer access Firefox.

When I click on the Icon to access I keep getting the following error message as per the attachment:

I have uninstalled Firefox and re-installed it THREE TIMES already', but I still get the same error as before, as per the screen print provided.

I have even tried to install Firefox with custom settings, but then in order to proceed with the installation the ONLY button to proceed was the "UPGRADE" option.

I am at my wits end because this is totally unacceptable and the updated version obviously DOES NOT WORK!!!

Your urgent attention and prompt action in sorting this out will be appreciated, thanks.

Hettie