Certain Firefox problems can be solved by performing a Clean reinstall. This means you remove Firefox and any leftover program files and then reinstall Firefox. Please follow these steps one by one:

1. Download the latest Desktop version of Firefox from http://www.mozilla.org and save the setup file to your computer.
2. After the download finishes, close all Firefox windows (click Exit from the Firefox or File menu) and confirm all upcoming messages.
3. Now, uninstall Firefox by following the steps mentioned in the Uninstall Firefox article.

IMPORTANT: On Windows, the uninstaller has the option to remove your personal data and settings. Make sure that you do not check this option; otherwise all of your bookmarks, passwords, extensions, user customizations and other Firefox user profile data will be removed from your computer.

After uninstalling Firefox on Windows, delete the "Mozilla Firefox" program folder, located by default in one of these locations:

• (On 32-bit Windows) C:\Program Files\Mozilla Firefox
• (On 64-bit Windows) C:\Program Files (x86)\Mozilla Firefox

1. Go to the Windows Start menu and click on "Computer".
2. In the Explorer window that opens, double click Local Disk (C:) to open the C:\ drive.
3. Find the "Program Files (x86)" folder or "Program Files" folder.
   • On 32-bit Windows, double-click the Program Files folder to open it.
   • On 64-bit Windows, you will see a "Program Files (x86)" folder AND a "Program Files" folder. Open the Program Files (x86) folder.
4. Look for a Mozilla Firefox folder. If you find one, right-click it and select Delete and confirm that you want to move the folder to the Recycle Bin.

Now, go ahead and reinstall Firefox:

1. Double-click the downloaded installation file and go through the steps of the installation wizard.
2. Once the wizard is finished, choose to directly open Firefox after clicking the Finish button.

Please report back to see if this helped you!

I followed your instructions ... multiple times ... to no effect. The Firefox.exe *32 process appears in Windows Task Manager (multiple times). But the program never initiates. Help,PLEASE! I am reduced to using IE.

Mary

Can you start Firefox in Safe mode?

You can use one of these to start Firefox in Safe mode:

• On Windows, hold down the Shift key while starting Firefox with a double-click on the Firefox desktop shortcut
• On Mac, hold down the Options key while starting Firefox
• Help > Restart with Add-ons Disabled

• https://support.mozilla.org/kb/Safe+Mode

A possible cause is security software (firewall,anti-virus) that blocks or restricts Firefox or the plugin-container process without informing you, possibly after detecting changes (update) to the Firefox program.

Remove all rules for Firefox and the plugin-container from the permissions list in the firewall and let your firewall ask again for permission to get full unrestricted access to internet for Firefox and the plugin-container process and the updater process.

See:

• https://support.mozilla.org/kb/Server+not+found
• https://support.mozilla.org/kb/Firewalls

See also:

• http://kb.mozillazine.org/Browser_will_not_start_up

Firefox now starts up and works pretty well. But it keeps crashing with a problem in ntdll.dll. I have tried to update this dll... but I can't find out how to do this. Can you help?

We're sorry to hear that your Firefox seems to be crashing. Please perform the following steps to give us a crash report ID that helps us find out more about the cause of the crash.

1. Enter about:crashes in the Firefox location bar (that's where you enter your website names) and press Enter. You should now see a list of submitted crash reports.
2. Copy the most recent 5 report IDs that you see in the crash report window and paste them into your forum response.

Thanks in advance for your help!

More information and further troubleshooting steps can be found in the Troubleshoot Firefox crashes (closing or quitting unexpectedly) article.

Try to boot the computer in Windows Safe mode with network support (press F8 on the boot screen) as a test to see if that helps.

75e37dd5-465c-45c2-ad07-c9f246f2d1bf12/9/20129:48 AM 455e11a8-63d7-4c78-ac17-735e3d0fb25b12/8/20123:14 PMd8d4d7ae-b501-41ae-8f45-aa67099febd812/5/201210:23 PM9e2dc92f-1162-41f0-bb25-705fcbdc188911/29/20129:17 PM

These reports were never sent to Firefox. Firefox also doesn't completely shut down when it crashes. firefox.exe *32 remains running ... often multiple times. If I want to restart Firefox, I have to use the task manager to stop this process before Firefox will start again. The above reports are in the Pending folder and there are only these four. PS: I have reinstalled Firefox a number of times. Mary

Help!!!!! I just installed the 17.1 update and now Firefox won't open at all. Mary

Any update on a resolution? I also have an XP user that had their Firefox stop working. Click on icon and it never opens but does start firefox.exe process in tast manger. Tried uninstalling as admin, deleting all Mozilla folders and reg keys, and rolling back OS 10 days to when user said it was working... nothing has worked so far. Also ran 1 virus scan that came back clean.

You need to provide us the crash ID's (they need to start with BP-) in order for us to do anything. Your crash might be different.

Firefox seems to be working OK now. I am prettysure that a Microsoft update affected a file called ntdll.dll. That popped up on a number of error reports, from program other then Firefox as well. But a later MS update seems to have fixed it, as those messages have gone away.

I haven't tried to reinstall my Plug-ins though. Mary

same issue for about three months now. I can't pin what I do to initiate it either. I suspect it is some how a conflict with adobe flash. So what happens is I click the firefox icon and it thinks for a moment and then nothing happens. If i go into task manager it shows its running in processes but not in application. Restoring my system doesn't fix it, restarting my computer doesn't fix it, reinstalling firefox fixes it until I restart my computer and then its back to square one. yesterday I fixed it by disableing the anamate windows function in my system adminstration panel and it worked until i shut down my computer. spy ware programs don't show a problem, i have spy bot and windows and i've run them both, so far i've spen twelve hours this week troubleshooting this problem and i'm about to switch to google chrome. windows is updated, I have the latest version of firefox java and flash. I cant start it up in safe mode, and because it won't start at all I can't reset any of the settings. to top it all off yesterday the program wouldn't even let me uninstall it and I had to start my computer in safe mode and remove it the hard way. i've been using fire fox for seven years with no problem and I really don't want to have to quit but i've wasted enough time trying to fix the thing.