[P3D] How to rebuild P3D shaders
In some cases, you may find yourself needing to rebuild your Prepar3D 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.

Please note: It may take between 10 seconds and 2 minutes for the shaders to re-generate when you launch Prepar3D after following the above steps.
You will also need to re-adjust your Graphic settings after deleting the Prepar3D.cfg.
Thank you to Avsim moderator Elaine Dixon for providing these steps.