I have tried everything I've run across for "A copy of Firefox is already open. Only one copy of Firefox can be open at a time."

Question

I had to fully erase all Mozilla/Firefox files from my Mac (OS X), including my profile (I backed up the bookmarks first). I had to as there were issues pointing to erasing it completely as a last step.
I have a two-fold issue.
One is that I kept deleting all found files because, even with my user profile eradicated, it still filled in bookmarks and forms, even with cookies cleared, history blown away and the proper boxes unchecked. Rebooting my computer did not provide any fixes, either.
Upon one more install, I started begging the error in the title of this post.
I cannot find any Firefox/Mozilla processes running. I cannot find a .parentlock file.
I have tried all the suggestions in these places:
[https://support.mozilla.org/en-US/questions/672361?as=aaq]
[https://support.mozilla.org/en-US/questions/904422?as=aaq]
[https://support.mozilla.org/en-US/questions/666513?as=aaq]
[http://kb.mozillazine.org/Profile_in_use#Remove_the_profile_lock_file]
None of these suggestions provided a solution. I tried looking for them several times.
Today has, overall, been a technological nightmare in many ways.
Please assist.
Thank you,
Heather

Answer 1

How did you remove the Firefox profile folder(s)?
Did you remove the profiles.ini file as well?
*http://kb.mozillazine.org/profiles.ini_file
*http://kb.mozillazine.org/Profile_folder_-_Firefox
You need to remove the profiles.ini as well to force Firefox to create a new default profile folder.
*http://kb.mozillazine.org/profiles.ini_file
*https://support.mozilla.org/kb/Firefox+is+already+running+but+is+not+responding
*http://kb.mozillazine.org/Profile_in_use