Firefox is already running but is not responding" error message - How to fix it

Question

I am not sure where to post this. But after trying everything from this site I came to my own fix.
This stopped the failure to close problem in Firefox [please pardon my lack of computer terms]
#1 Uninstalled Firefox and re-installed it and it still didn't restart correctly
#2 Start menu [ %APPDATA%\Mozilla\Firefox\Profiles\ ] and deleted all firefox files
#3 Uninstalled Firefox and re-installed again
#4 Start menu [firefox.exe -p ] and deleted profile info and created a new profile
#5 Open Firefox Right clicked for Menu Bar
#6 select Tools
First off I did change my start page and I unchecked all Tab buttons [i don't like tabs]
#7 Privacy Tab
check-- [Tell sites I do no want to be tracked] [may be optional]
check-- [Never Remember History] ******** and firefox restarted
Location Bar-- check-- or select-- [ Nothing ] [may be optional]
then clicked ok
Then I again tried my old setting of [use custom settings for history ]
When I changed the [Never Remember History] to [use custom settings for history] and restarted firefox.
I attempted to try this and all the restart problems popped up again
Please note
This could not be Undone. Attempting to change from [use custom settings for history] back to [Never Remember History] would not correct the hang problem, so I had to start all over from the beginning. And that did work.
I did loose my Bookmarks in the reset but I will live with it!
I have restarted 20 times without a failure where it was two or three times. so it seems to work now.
Sorry about my poor message abilities above. As I get older my attention to detail seems to be falling a bit.
To cap what this is about.
I started into checking the [options] page and with every page I altered I clicked yes and closed. Then checked for a response in Firefox.
Everything worked fine until I got to the Privacy Tab.
Again I am sorry about my crappy writing.
Perhaps you smart folks can figure a way to fix this without loss of data.
Good Luck gwinslo

Answer 1

Hi there, gwinslo. You have come to the right place.
From what I have been reading from other posts on this forum, the issue may
be caused by the clear history settings.
Press the '''<Alt>''' or '''<F10>''' key to bring up the tool bar. Then '''Tools > Options > Privacy'''.
The button next to '''History''', select '''Use Custom Settings'''.
At the bottom of the page, turn on '''Clear History When Firefox Closes.'''
At the far right, press the '''Settings''' button. Turn on ONLY '''Cache''' and
'''Form And Search History''' leaving the others off.
'''https://support.mozilla.org/questions/997866?esab=a&s=&r=1&as=s''' {web link}
This is not a cure but will make it easier if Firefox locks up.