In some cases, you may find yourself needing to rebuild Prepar3D's shaders. To do this, follow the steps below.
1) Navigate to the Prepar3D.cfg location and delete the "Prepar3D.cfg" file. The location of this file is listed below:
Local Disk (C:) ► Users ► You ► AppData ► Roaming ► Lockheed Martin ► Prepar3D v4 ► Prepar3D.cfg
2) Navigate to the Prepar3D "Shaders" folder and delete the "Shaders" folder. The location of this folder is listed below:
Local Disk (C:) ► Users ► You ► AppData ► Local ► Lockheed Martin ► Prepar3D v4 ► Shaders
3) Launch Prepar3D. Both of the "Shaders" folder and the "Prepar3D.cfg" will be automatically regenerated.