I am sharing the solution to my recent technical problem of not having the VST version of Sytrus load, using FL Studio. Note: I own FL Studio Producer Edition, and the VST plugin Sytrus. (2 different register keys to unlock both products)
I had installed the vst and registration keys correctly, but still only the DEMO version would load.
If this happens for you, here is what fixes it. Go to Channels/More... Then a window comes up that says Select Generator Plugin. Here you can select which one loads, the DEMO, or Sytrus VSTi.
Now it works!
Love this plugin!