Do you recognize these problems?
P3D takes too long to start?
Transparent cockpit textures with activated panel lights?
Add-on won’t launch?
Use a shortcut in the root of P3D4 installation folder called Delete Generated Files.
Before you go !
Empty your Recycle bin in Windows…and backup these 2 default folders to your desktop for later use
?:\Documenten\Prepar3D v4 Files
?:\Documenten\Prepar3D v4 Add-ons
What does Delete Generated Files do?
It activates %COMSPEC% /C “Prepar3D.exe -deletegenerated” and will reset P3D4 to default after a restart.
Which files and folders are removed to the Recycle bin?


Where they come from (1)?
C:\ProgramData\Lockheed Martin\Prepar3D v4
Files and Folders: [add-ons.cfg ./. weather.cfg]
Where they come from (2)?
C:\Users\yourname\AppData\Local Roaming\Lockheed Martin\Prepar3D v4
Files and Folders:
/Controls + /Effects + /Shaders + Prepar3D_Default.fxml and Prepa3D_Default.wx
[Folders and Files:: /Controls/ ./. /Shaders/]

Where they come from (3)?
C:\Users\yourname\AppData\Roaming\Lockheed Martin\Prepar3D v4
Files and Folders: [add-ons.cfg ./. WindowDefinitions.xml]\
What do you need to restore?
- sort your recycle bin hitting the name column.
- restore both dll.xml ( in order to run apps started by dll.xml).
- restore both exe.xml ( in order to run apps started by an exe in exe.xml).
- restore simobjects.cfg (your connection with e.g. IVAO_MTL).
- restore both \Controls\ folders (your hardware settings).
- restore VehicleFavorites.xml (your vehicle favorites settings).
- Start the sim; do not activate Add-on.xml’s for the moment.
- Check the contents of the scenery library; disable Bathymetry (Prio=1) unless you want to fly below sea level … wait for rebuilding the database.
- ORBX Users: settings are gone … don’t shut down the sim …
- Rename C:\Users\yourname\AppData\Roaming\Orbx into
C:\Users\yourname\AppData\Roaming\Orbx-old
- Goto https://orbxdirect.com/central and download ORBX Central
- Install ORBX Central
- Check the scenery library: FTXAA_ORBXLIBS is Prio 1.
- Check for anomalies… all OK? then delete the …\ORBX-old folder
- Run C:\P3D4\ORBX\Troubleshooter\MigrationTroubleshooter.exe
- When installed, lines must record MIGRATED CORRECTLY, else reinstall corrupted or missing scenery.
- Corrupted lclookup.bgl ?? Read our post 2020-59
- Rename C:\Users\yourname\AppData\Roaming\Orbx into
- Select Options from the P3D4 Scenario Menu.
- Uncheck Pause on task switch in General/Application.
- Bullet Ignore crashes and damage in General/Realism.
- Set your required Display Global Settings in Options/Display.
- Close, then …
- Run the default flight once, shut down the sim and restart PC.
- Select Add-ons from the Prepar3D Scenario screen.
- Enable Add-ons 1-by-1 and test for anomalies. If so … read this.
- Select Scenery from the Prepar3D Scenario screen
- Add Area to add scenery manually and test for anomalies. If so … read this.
- Remember that (as a good habit) all apps must Run as Administrator
- More Questions? Click here.
Version 2020-03-19