Also, I keep either trying to login or use the regkey and nothing is happening.
It was working earlier. Not sure what has happened, but now I only see the screen in the attached screenshot ...
FLStudio is open. Any monitor changes being made should be done while FLStudio is closed to avoid this issue.
Solution
In order to recover your off screen plugins you must perform a manual reset of your FL ...
Please help can't Resize - FL takes up the whole screen (not maximised)
Unable to Move or Resize the window < > < >
I'm using Mac OS X El Capitan 10.11.6 - FLStudio 20 ...