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Firefox won't start. I followed all troubleshooting recommendations i found on this site and still nothing. please help.

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New Contributor

Firefox won't start. I followed all troubleshooting recommendations i found on this site and still nothing. please help.

Firefox worked on this computer in the past. Now, Firefox wont start.

1. I deleted everything off this computer including the profile and all files under C:\Program Files (x86)\Mozilla Firefox\

2. I deleted my profile here: %APPDATA%\Mozilla\Firefox\Profiles\

3. I uninstalled the program, deleted all cookies, temporary internet files etc. I restarted my computer.

When I reinstalled it, it still doesn't open. When I ctrl+Alt+del I see the process (not application) is running, but nothing appears on the streen Please help!!! win 7, plenty of ram, plenty of disk space, high speed internet

7 REPLIES
Legendary Contributor

Re: Firefox won't start. I followed all troubleshooting recommendations i found on this site and still nothing. please help.

Hello chandlercrouch, If you deleted your only profile folder, and now seeing the "already running" dialog box, delete or rename the profiles.ini file in the profile folder path. A new default profile will be created when you next start your Mozilla application.


thank you

Site Moderator

Re: Firefox won't start. I followed all troubleshooting recommendations i found on this site and still nothing. please help.

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:

New Contributor

Re: Firefox won't start. I followed all troubleshooting recommendations i found on this site and still nothing. please help.

@ideato the profile isn't an issue. I deleted the profile folder, all cookies etc, and uninstalled firefox to make sure my system was clear of any previous settings that could mess things up... then I installed firefox. Upon installation, firefox created a completely new profile.

@cor-el I completely disabled all security, then reinstalled and observed no changes.

I sincerely appreciate both of your replies. Do you have any other ideas about what could be causing the problem?

Legendary Contributor

Re: Firefox won't start. I followed all troubleshooting recommendations i found on this site and still nothing. please help.

The profiles.ini file contains information used to keep track of profiles in Firefox, if you have a new profile but you can not open it then delete the profiles.ini file.

the profiles.ini file it is not inside profile folder. it is in %APPDATA%\Mozilla\Firefox , but not inside profile folder


thanks again

Site Moderator

Re: Firefox won't start. I followed all troubleshooting recommendations i found on this site and still nothing. please help.

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. I followed all troubleshooting recommendations i found on this site and still nothing. please help.

@cor-el ahhh, thank goodness... progress. You're smart. It started in safemode. It feels great, but doesn't solve the problem entirely. How do I troubleshoot from here?

I just executed the plugin for the automatic trouble shooter. It saved a bunch of stuff under my original question post.

Site Moderator

Re: Firefox won't start. I followed all troubleshooting recommendations i found on this site and still nothing. please help.

Which problems are still left?

If it works in Windows Safe mode then you have a problem with other software, likely security software or a system driver, that is running on your computer.
Make sure that you have the latest updates of your security software.

You can use the Autoruns utility to see which software and services gets started, but be careful with disabling services.