Firefox Community Forum

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

Mozilla Firefox is very slow and even difficult to open.....I am using this browser since ten years and never had any problem....Please do the needful at your earliest...Thank a lot....RASIK MER

Please tell me how to resolve this issue. The 3 reports I have submitted from the crash window are:

Crash ID: bp-4107d3db-4280-445b-a0cd-e96400251020 [10/20/2025 2:43 PM (Pacific)] Crash ID: bp-b5e0bbf3-d4f6-4b2a-898a-f56960251020 [10/20/2025 2:40 PM (Pacific)] Crash ID: bp-975fcb26-5886-492f-8253-e37820251020 [10/20/2025 2:39 PM (Pacific)]

Mozilla Firefox is very slow and even difficult to open.....I am using this browser since ten years and never had any problem....Please do the needful at your earliest...Thank a lot....RASIK MER

I launch Firefox from a shortcut in the QuickLaunch bar. I need to double-click that to get a response. But then TWO instances of Firefox open, and I have to close one - which seems a waste of time and effort over and over and over. My system is x32Win10ProV22H2. How to get just one instance ?

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!

When opening Firefox version 147 it asked if I wanted to install updates and after answering affirmative, then it gave "Error: Platform version '147.03' is not compatible with minversion >=147.02 maxversion <=147.02. Maybe try to reinstall Firefox?" The browser will not open. What is the workaround??

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

I can't open FIrefox. When I try to open it I get the following error message. "Firefox is already running, but is not responding. The old Firefox process must be closed to open a new window." I opened Task Manager and could not find any instance of Firefox or Mozilla running. I uninstalled Firefox and deleted all the files and folders having to do with Mozilla and Firefox. Then I reinstalled Firefox. I continue to get the same error message. I am running Windows 11 64bit on a Dell laptop. Any suggestions? Ray