cancel
Showing results for 
Search instead for 
Did you mean: 

Firefox won't start

Highlighted
New Contributor

Firefox won't start

I had Firefox running with probably 8 windows. I closed them all, plus other programs and rebooted the machine. After that Firefox wouldn't start. I have uninstalled and re-installed twice. The Profile manager won't run ... so I manually removed the preferences. I have tried clicking on the desktop icon, right clicking, right-clicking the firefox.exe entry in the file manager. And nothing happens. The firefox.exe *32 process appears in the task manager ... but the program isn't running. Absolutely nothing happens.

I am running Win 7 on a ACER laptop with an I5 processor and 4Gb of memory.

Tags (2)
12 REPLIES
Site Moderator

Re: Firefox won't start

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 (CSmiley Happy 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!

New Contributor

Re: Firefox won't start

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

Site Moderator

Re: Firefox won't start

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

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:

See also:

New Contributor

Re: Firefox won't start

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?

Site Moderator

Re: Firefox won't start

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 Firefox crashes - Troubleshoot, prevent and get help fixing crashes article.

Site Moderator

Re: Firefox won't start

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.

New Contributor

Re: Firefox won't start

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

New Contributor

Re: Firefox won't start

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

New Contributor

Re: Firefox won't start

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.