Check that you still have the default profile as listed in the file profiles.ini as Default=1.

If profiles.ini is present, but the profile that is marked in profiles.ini as Default=1 is missing then delete profiles.ini to make Firefox create a new default profile.

• http://kb.mozillazine.org/profiles.ini_file
• http://kb.mozillazine.org/Recovering_a_missing_profile
• http://kb.mozillazine.org/Profile_in_use

See also "Hang at exit":

• http://kb.mozillazine.org/Firefox_hangs
• https://support.mozilla.com/kb/Firefox+hangs

I tried looking everywhere for a solution but no luck.I installed aurora instead of firefox. After install, I click to open and it says its already running, either kill process or restart pc. I go to task manager but its not listed anywhere not even in services. So I attempted to restart my pc. After reboot, I try clicking firefox and same error message. I don't know why this is happening because this is a complete fresh system build and install. Why would I get this error? There's no parent lock file, no running process or service.

Any ideas?

Did you create a new profile for the Aurora version, assuming that you still have the regular release as you should because there can be problems with Aurora test builds?

• http://kb.mozillazine.org/Creating_a_new_Firefox_profile_on_Windows
• http://kb.mozillazine.org/Shortcut_to_a_specific_profile
• http://kb.mozillazine.org/Using_multiple_profiles_-_Firefox

Did you check if there is a profiles.ini file?

• http://kb.mozillazine.org/profiles.ini_file

I have regular release. It won't open to do anything. I just installed it and it I get that error. So no profile or anything was made.

Download a fresh Firefox copy and save the file to the desktop.

• Firefox 12.0.x: http://www.mozilla.org/en-US/firefox/all.html

Uninstall your current Firefox version, if possible.

• Do NOT remove personal data when you uninstall your current Firefox version, because all profile folders will be removed and you will also lose your personal data like bookmarks and passwords from profiles of other Firefox versions.

Remove the Firefox program folder before installing that newly downloaded copy of the Firefox installer.

• It is important to delete the Firefox program folder to remove all the files and make sure that there are no problems with files that were leftover after uninstalling.
• http://kb.mozillazine.org/Uninstalling_Firefox

Your bookmarks and other profile data are stored elsewhere in the Firefox Profile Folder and won't be affected by a reinstall, but make sure that you do not select to remove personal data if you uninstall Firefox.

• http://kb.mozillazine.org/Profile_folder_-_Firefox

See also:

• https://support.mozilla.org/kb/Firefox+is+already+running+but+is+not+responding
• http://kb.mozillazine.org/Profile_in_use

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

That did nothing. I did a complete uninstall or everything. I installed a fresh FF and I still get the same error.

Did you try to create a new profile?

See "Basic Troubleshooting: Make a new profile":

• https://support.mozilla.org/kb/Basic+Troubleshooting#w_8-make-a-new-profile

See also:

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Thats not going to work because firefox won't open. I can't make a new profile. I can't o anything with firefox since it won't open. Somehow its running but its not in my processes or services. I just installed it\Clicked icon to open\Get error saying its already running. I searched every where and its not running at all. So to make a profile, disabling add-ons (which there are none) or anything that envolves doing within firefox, I can not. I already did a complete uninstall or everything (bookamrks, passwords, data) Wiped away all files left over after uninstall, restated pc. Re-downloaded a second copy or latest version, Re-installed fresh Firefox and I still get the error That its running. So after all that, it seems like I did nothing since nothing changed at all.

You can try to rename or move the profiles.ini file to force Firefox create a new profile.

• http://kb.mozillazine.org/profiles.ini_file
• http://kb.mozillazine.org/Profile_folder_-_Firefox

So basically, locate profile.default folder and delete it? is that right? That way it will create a new profile by default and should then open.

I finally got it open. I deleted everything that had profile in it. Thanks soo much. I know this seemed frustrating to you but it was even worse to me. Now I need to read on moving a profile from another pc to this one so I get all my stuff back.

Thanks a million

You're welcome