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Firefox will not start

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Firefox will not start

When I click on either Firefox or Thunderbird, I get the: "Firefox (Thunderbird) is already running but is not responding" error message.

I tried all of the sloutions in the help suggestions, and none work.  When I access my profile, the parent.lock file is not there.  All other solutions listed do not work.  Both programs were working earlier this evening, but Thunderbird kept downloading my mail from the server multiple times, loading the same messages over and over every time it checked for mail.  It has never done this before.  Firefox was performing ok.  I restarted the computer to try to fix the Thunderbird problem when this Firefox problem surfaced also.  

I tried a system restore. NO help I tried to update. NO help I tried to uninstall and reinstall. No help.

I will perform an in depth virus scan tonight. Also after I restarted the first time, my anti-virus software was disabled. Seems the only time I have had that problem was when my system was infected.


Win 7 HP tower Latest version of Firefox and Thunderbird. Automatic updates for both are on.

Thanks for any help

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Accepted Solutions
Site Moderator

Re: Firefox will not start

Do you have a profiles.ini file?

A possible cause of this happening is if the profile that is marked as Default=1 in the profiles.ini is missing and in such a case you can delete the profiles.ini file to force Firefox to create a new profile.
If this happens with Thunderbird as well then it is possible that an older version of the file has been restored or that Firefox wasn't able to update the profiles.ini file after a reset or creating a new profile.

1 REPLY
Site Moderator

Re: Firefox will not start

Do you have a profiles.ini file?

A possible cause of this happening is if the profile that is marked as Default=1 in the profiles.ini is missing and in such a case you can delete the profiles.ini file to force Firefox to create a new profile.
If this happens with Thunderbird as well then it is possible that an older version of the file has been restored or that Firefox wasn't able to update the profiles.ini file after a reset or creating a new profile.