Learn how to completely uninstall Prepar3D, deactivate its licence, remove add-ons and delete leftover AppData, ProgramData and scenery files.
To completely uninstall Prepar3D, deactivate its licence if the computer will be replaced or wiped, uninstall third-party add-ons, then remove Prepar3D through Windows. Reboot and delete the version-specific installation, ProgramData, AppData and Documents folders left behind. Back up aircraft, scenery, controls and flight files you intend to reuse.
What should I back up before uninstalling Prepar3D?
Back up irreplaceable user content, but avoid copying generated files that could reproduce the problem behind a clean reinstall.
- Saved flights, scenarios and flight plans
- Control profiles, camera settings and carefully tuned configuration files
- Custom aircraft, liveries, scenery, effects and gauges that lack separate installers
add-on.xmlpackages and a record of their external installation locations- Licence details and installers for Prepar3D add-ons
Our Prepar3D backup and version-folder checklist identifies the files most likely to matter. Do not plan to restore the entire old AppData or ProgramData folder after a clean installation; that can put a damaged configuration, scenery index or add-on registration straight back.
How do I completely remove Prepar3D from Windows?
- Close Prepar3D and related utilities. Exit weather engines, traffic tools, add-on managers and any background programs connected through SimConnect.
- Uninstall third-party add-ons first. Use each product's normal uninstaller while Prepar3D is still present. Deactivate licensed add-ons where required. This prevents broken Windows entries and makes externally installed files easier to identify.
- Open the Windows application list. Use Installed apps or Apps & features in Windows Settings, or Programs and Features in Control Panel. Locate the entry for the exact Prepar3D major version and licence edition being removed.
- Run the Prepar3D uninstaller. If the Client uninstaller asks about deactivation, choose Yes when retiring the installation, moving it to another computer or wiping Windows. Choose No only when reinstalling the same version on the same licensed machine and retaining its activation.
- Remove remaining components. Depending on the Prepar3D version, Windows may list Client, Content and Scenery packages separately. Remove any same-version components that remain, along with that version's SDK if it was installed. Do not remove components belonging to another Prepar3D major version.
- Restart Windows. This releases locked files and completes pending installer operations.
- Delete the residual folders. Remove only folders carrying the version name you uninstalled, using the locations below.
If an uninstall entry is damaged, run the matching Prepar3D installer and use its repair or removal option. Manually deleting the installation directory first usually makes a broken uninstall harder to correct.
Which Prepar3D folders can I delete?
A clean removal includes the main installation and the version-specific folders in ProgramData, AppData and Documents. Replace vX with the major version being removed; folder names can vary slightly between releases and licence editions.
| Location | What it may contain |
|---|---|
Prepar3D installation directory, commonly %ProgramFiles%\Lockheed Martin\Prepar3D vX | Core simulator files and add-ons installed directly inside the simulator |
%PROGRAMDATA%\Lockheed Martin\Prepar3D vX | System-wide scenery configuration, indexes and add-on discovery records |
%APPDATA%\Lockheed Martin\Prepar3D vX | Prepar3D.cfg, user configuration, controls and camera data |
%LOCALAPPDATA%\Lockheed Martin\Prepar3D vX | Shader and other generated caches |
%USERPROFILE%\Documents\Prepar3D vX Add-ons | Packages registered through add-on.xml |
%USERPROFILE%\Documents\Prepar3D vX Files | Saved flights, scenarios and related user files |
| Custom folders on other drives | External scenery libraries, aircraft packages, utilities and add-on-manager libraries |
ProgramData and AppData are hidden by default, but their environment-variable paths can be pasted directly into File Explorer's address bar. If several Windows accounts used Prepar3D, check each account's AppData and Documents folders.
Do not delete the parent Lockheed Martin folder when another Prepar3D version remains installed. Externally stored packages also survive removal of the simulator; our explanation of where Prepar3D v5 add-on scenery and add-on.xml packages are stored helps locate these libraries. Downloaded installers and backup archives are separate files and must be removed manually if the aim is to reclaim all disk space.
Should I delete Prepar3D registry keys or SimConnect?
Do not manually erase Prepar3D registry or licensing data during a normal clean uninstall. The official uninstaller should handle product registration and deactivation; deleting keys by hand does not reliably return an activation and can obstruct a later reinstall.
Leave shared SimConnect components, Microsoft Visual C++ runtimes, the Windows Installer cache and other common dependencies alone. FSX, another Prepar3D version and third-party utilities may still require them. Registry-cleaning software is unnecessary for a clean Prepar3D reinstall.
Clean-reinstall check
After deleting the version-specific folders, restart Windows and install Prepar3D into a fresh directory. Launch it once with a default aircraft and default scenery before adding anything else. Restore saved flights and control profiles selectively, then reinstall add-ons one at a time.
A mistake we see constantly is restoring the whole old configuration immediately, which cancels the clean test. If an unmodified installation still fails, follow our Prepar3D crash and residual-file troubleshooting steps before reinstalling third-party content.