Firefox won't load

Hello all. I have for some reason lost the ability to load and use the Firefox browser. It began a few weeks ago when I noticed that it would fail depending on how I initialized it on startup. Now it is completely unusable and fails with this message. I do not know how this happened as I did not remove or alter anything. I have attempted to remove and reinstall with no success although I have noticed that it is updating in I do a system update. Is this fixable? On this box I am running Netrunner 16.04 LTS w/6.0 GiB Ram on a HP desktop w/Intel Core i3-2120 CPU @ 3.30 GHz and 4 Cores.

See attachment for failure picture.

Thats not a firefox error message I see in the screenshot. Rather ksystraycmd error.
Though I am pretty sure that this functionality was removed from Plasma 5 anyways.
See this:

Thank you leszek for your quick reply. You are indeed correct that the error is generated as a ksystraycmd failure. It is generated anytime I try to load Firefox. Sorry for not making that clear. I just have not found out how to repair it yet. I did see the post of the link you supplied prior to posting this thread, but alas no solution listed there either. The part that is really confusing is why after a remove and fresh reinstall of Firefox am I still getting the same error message.

It is a setting or config that is stored somewhere else. Though I really don’t know where exactly.
I guess somewhere in ~/.config

OK, that is what I was thinking, and like you I do not know where and cannot find it. Thank you for your help anyway. I will keep looking.

It is more than likely a plugin causing the crashing issue.
Look under ~/.mozilla/firefox/{user account}/extensions and delete or move (backup) the user installed plugins.