How do I update Prepar3D safely without breaking add-ons?

Update Prepar3D safely by treating a point update and a major-version upgrade differently. Back up your configuration, confirm that every essential add-on supports the target build, disable third-party packages, then update only the Client, Content and Scenery components named in the release notes. Re-enable and test add-ons in small groups.

What should I do before updating Prepar3D?

A recoverable Prepar3D update starts with a complete configuration backup and an add-on compatibility check. Do not rely on a copy of Prepar3D.cfg alone.

• Record both versions: note the exact Prepar3D build installed and the build you intend to install.
• Check essential add-ons: aircraft, weather engines, camera tools, traffic programs, shader tools and anything loading a native DLL may require an exact simulator build. Our explanation of compatibility differences between Prepar3D v4, v5 and v6 covers why a matching major version matters.
• Copy configuration folders: back up %APPDATA%\Lockheed Martin\Prepar3D vX, %PROGRAMDATA%\Lockheed Martin\Prepar3D vX and the applicable Prepar3D add-ons folder under Documents. Here, vX means your installed major version.
• Preserve external packages: copy or record the paths of scenery, aircraft and other packages stored outside the simulator. Include controller profiles, saved flights and files such as add-ons.cfg, dll.xml and exe.xml where present.
• Keep installation details: retain the installers and activation information for add-ons you may need to update or reinstall.

Copy these files rather than moving them. A Windows restore point is useful for system changes, but it is not a substitute for backing up Prepar3D data.

Is this a point update or a major Prepar3D upgrade?

A point update within one major Prepar3D version can often use selected component packages, while a move between major versions should be treated as a new simulator installation.

Do not assume that an add-on labelled for Prepar3D supports every major version. A move such as v5 to v6 is not a routine patch; the scope of the Prepar3D v6 change illustrates why add-on support must be verified before migration.

The safe Prepar3D update sequence

The safest order is to isolate third-party content, update the required simulator components, test a clean start and then restore add-ons gradually.

1. Read the release notes: determine whether the update changes the Client, Content, Scenery or more than one component. Do not update every package automatically if the instructions call for only one.
2. Disable third-party content: use the simulator's add-on controls or the add-on's own manager where available. Untick traditional Scenery Library entries and record any package you disable. Avoid deleting registrations or editing XML files without a backup.
3. Close connected programs: exit Prepar3D and stop weather, traffic, camera, network and hardware utilities that connect to it.
4. Update only the required components: for a component update, remove only the old instance of the named component through Windows' installed-apps control, then install the matching replacement package. Do not uninstall the whole simulator for a Client-only update, and never delete the core folder by hand.
5. Start Prepar3D without add-ons: load a default aircraft at a default airport and confirm that the simulator reaches the flight, menus work and no module errors appear. The first start may take longer while generated data is rebuilt.
6. Install compatible add-on updates: apply versions made for the new Prepar3D build before enabling their packages.

Add-ons stored outside the simulator are less likely to be overwritten. For scenery, the method described in our guide to keeping Prepar3D v5 scenery external with add-on.xml also reduces duplicate registrations and makes later updates easier to diagnose.

Should I install only the Prepar3D Client update?

Install only the Client when the release notes say that Content and Scenery do not need updating for the fixes or features you require.

• Client contains the simulator executable and core program components.
• Content covers assets such as default aircraft, effects and related files.
• Scenery contains base scenery and world data.

A Client-only update is not automatically safer if the release also depends on revised Content or Scenery. Conversely, unnecessarily reinstalling Content can overwrite modified default assets. Let the release documentation, not the package size, decide.

How should I re-enable add-ons after the update?

Re-enable add-ons by category and restart Prepar3D between groups so the last change remains easy to identify.

1. Foundational libraries and required object packages
2. One scenery region or airport group
3. Weather and traffic programs
4. Aircraft, one complex product at a time
5. DLL-based utilities, shader tools and camera programs

Test the same default flight after each group, then test the add-on's normal scenario. A mistake we see constantly is enabling an entire add-on collection at once; when Prepar3D then fails during loading, there is no clear suspect.

What if Prepar3D crashes after the update?

Start by disabling the last add-on group enabled, then distinguish a damaged configuration from an incompatible module before reinstalling anything.

1. Return to a clean start: disable all third-party packages and confirm whether default Prepar3D loads.
2. Check the faulting module: Windows Event Viewer may identify an add-on DLL, although a core module named in the crash does not always mean that core file caused it.
3. Rebuild generated settings: rename Prepar3D.cfg and let the simulator create a fresh one. Reapply settings selectively instead of restoring the old file wholesale.
4. Clear shaders only when relevant: with Prepar3D closed, rename or remove the Shaders folder beneath the simulator's %LOCALAPPDATA% directory if the problem involves black graphics, display corruption or a graphics-related start-up failure.
5. Repair before reinstalling: repair the affected Prepar3D component, then test it without add-ons. For terrain-related failures, follow our staged procedure for diagnosing Terrain.dll crashes.

Do not copy an old DLL into the updated simulator or restore an entire core-folder backup over new files. If one add-on triggers the failure, it needs a compatible build or must remain disabled; reinstalling Prepar3D will not make an incompatible module compatible.