Hello Keven,
I'm also having an issue. I have both Prepar3d version 3.4.18.19475 and FSX. The Majestic Q400 is installed into both simulators. After installing the effects I was able to experience the effects in FSX and they are really nice. You did a great job. However, the effects do not show up in P3D. I read the manual very carefully and tried the weather options listed in the manual. No joy. I then uninstalled the Q400 and reinstalled version 1.018B along with the 1.018B-E patch. None of that worked. I uninstalled Prepar3D and then reinstalled the latest version. None of that worked. Pressing the letter "I" has no effect either. I load both simulators the same way, I start out at a default location with a default aircraft. After that has loaded I move to the location of choice in the default aircraft and then switch to the Q400. I do this for both simulators. FSX works wonderfully! What do I need to do or look for in P3D to make it work? Thank you for all your help.
Don