Error when opening links from external places with Firefox

Windows 10
My default browser is Firefox (running 66.0.5) and I have multiple profiles setup.
Whenever I open a link from somewhere like Discord, it will pop up with this error.

Clicking the cross in the top left will close the box without opening the requested link. Clicking "Close Firefox" will restart Firefox and open the link in a new tab along with the tabs which were already open but this can be quite annoying as I may have to find where I was up to in something like a youtube video.

My question is if there is a way for clicking a link in an external application to open in Firefox without opening that dialogue box.

Sounds like you have add ons in firefox that are making the system think FF is actually running when it may not be.

Check task manager for any FF related entries and close them as a test and then try the link again.

In a nutshell, Firefox is already running in some respect :)

I disabled all my add-ons and tried to open a link (google in this case) the same error popped up.
For task manager i'm not sure which processes to close. I had one tab open and Firefox showed 3 after i expanded the process.

Ending the top one did nothing to Firefox, i opened a link but error popped up
Ending the second one crashed the tab, opening a link made the error come up
Ending the third one closed the browser

This problem doesnt happen when firefox isnt open when i click the link.
It happens when specifically the default profile is already open. If i have a non default profile open, the link will open a new firefox window with the default profile.

I don't know if this applies in your case, butdo you by any chance normally start the default profile via a shortcut ? Only, if you do so, make sure there isn't "-no remote" set in that shortcut property.

Quote:
"Important: Never use -no-remote to start the "default" profile (the one that is set to open without asking when you launch Firefox). That's because when you launch Firefox, for example, by clicking a link in your mail program, you will get a Firefox is already running but is not responding message if the default profile is already in use. The solution is to always start the default profile normally and launch all others with -no-remote."
Opening a new instance of your Mozilla application with another profile - MozillaZine Knowledge Base

Just a thought.

Replying to Das10
Im not too sure what you mean by that but here are what my shortcuts look like (the "target" property is scrolled to the very end of the line in all 3 windows)
The 'Personal' profile is set as default.

Is this wrong or is this fine?

That's is fine; so there is something else going on.

Well i don't actually know what I did but something happened and its working again? It wasn't working, i went to shower came back and it was working? I'm really confused because this problem didn't start a few hours ago. Its been like this for while. But its fixed.

Well thanks for putting in the time to help fix my problem.