Fix the MSFS “Error preparing navigation data” message by isolating add-ons, reinstalling AIRAC data, rebuilding indexes and repairing packages.
To fix “Error preparing navigation data” in Microsoft Flight Simulator, first start the sim with an empty Community folder. If the message disappears, remove and reinstall the custom AIRAC/navdata package or conflicting airport add-on. If it remains, rebuild the simulator’s navdata indexes, then verify or repair the official packages.
What causes the navigation data error?
The error means Microsoft Flight Simulator could not combine or index one or more navigation-data sources. The simulator builds its database from core packages, airport and scenery records, and any custom AIRAC data installed on the PC.
| Where the error appears | Most likely cause | Best first action |
|---|---|---|
| During simulator start-up | Broken package, duplicate navdata or damaged index | Test with an empty Community folder |
| Only after an AIRAC update | Incomplete installation, wrong packages path or two cycles active | Remove the custom data through its installer |
| After installing an airport | Conflicting runway, navaid or procedure records | Disable that airport and test again |
| Only inside one aircraft | The aircraft uses a separate navigation database | Repair that aircraft’s AIRAC installation |
An interrupted simulator update can produce the same message by leaving an official package incomplete. A disconnected packages drive, insufficient free space or blocked write access can also prevent the database from being regenerated.
How do I fix “Error preparing navigation data” on PC?
On PC, an empty Community folder is the quickest reliable way to separate an add-on fault from a core-package fault.
- Close every related programme. Exit Microsoft Flight Simulator and close any AIRAC manager or add-on linker. Check that the simulator is no longer running in the background.
- Find the active packages location. Use the installation containing both the
CommunityandOfficialfolders. Do not assume the default location if you previously moved the packages to another drive. - Rename the Community folder. Rename
Communityto something such asCommunity.old, then start MSFS. The simulator may create a new empty folder automatically. - Use the result to choose the next fix. If MSFS now starts normally, an add-on is responsible. Restore packages in batches, restarting between tests. Add custom navdata and recently installed airports last; restoring half the remaining packages per test finds a conflict much faster than checking them individually.
- Cleanly reinstall custom AIRAC data. Remove every component through the same manager that installed it, launch MSFS once using its default database, close it, and install one AIRAC package for the correct simulator version and packages path. Our MSFS navdata update and clean-reinstall steps cover this process in detail. A mistake we see constantly is deleting only one part of a multi-package installation or leaving an older manual copy active.
- Rebuild the MSFS 2020 indexes. With the simulator closed, find its local cache or user-data location. If
Content.xmlexists, rename it by appending.old. Do the same with theSceneryIndexesfolder if present. MSFS recreates these records at the next start, which may take longer than usual. If either item is absent, skip it rather than creating it. MSFS 2024 handles parts of its package database differently, so use its built-in content repair rather than deleting undocumented database files. - Check storage and permissions. Confirm that the packages drive is connected, writable and has free space. If MSFS cannot recreate its indexes, check whether Windows security has blocked the simulator or AIRAC manager; do not disable security protection globally.
- Repair the official content. Install pending simulator and content updates, then use the platform client’s repair or verification function. Back up custom content first. On Windows, use Repair before any Reset option because resetting can remove local settings or downloaded packages.
What if the error returns after reinstalling AIRAC data?
If the error returns only after the AIRAC reinstall, the package is targeting the wrong simulator location or another navdata copy remains active. Remove it again, verify that default MSFS navigation data loads, and then check that the installer is configured for the correct MSFS 2020 or MSFS 2024 packages directory.
Keep only one custom AIRAC source active. Do not combine an old manually copied package with a manager-installed version, even when both claim to contain the same cycle. If navdata works until a particular airport is restored, update or remove that airport rather than repeatedly rebuilding the database.
Why does only one aircraft show a navigation database error?
An FMC or MCDU error confined to one add-on aircraft usually belongs to that aircraft’s private navigation database, not MSFS’s global database. Rebuilding the simulator indexes will not repair a separate aircraft database.
For PMDG aircraft, follow the separate PMDG AIRAC installation checks. Fenix users should instead use the Fenix A320 database procedure. Also make sure the route source and aircraft use compatible AIRAC cycles; a missing waypoint caused by a cycle mismatch does not mean the whole MSFS database is corrupt.
How do I fix the error on Xbox or PlayStation?
On Xbox, and on PS5 or PS5 Pro with Microsoft Flight Simulator 2024, isolate installed content because the ordinary PC Community folder is not exposed.
- Close the simulator fully. On Xbox, remove it from Quick Resume before restarting.
- Install all base-simulator and owned-content updates. Do not interrupt the content preparation stage.
- Disable or uninstall recently added optional airports and scenery. Test without them, then restore the content in small batches.
- Reinstall only as a last resort. Do this only when the error remains with optional content removed and all updates completed.
Microsoft Flight Simulator 2020 was not released for PlayStation, so PlayStation-specific troubleshooting applies only to MSFS 2024.
Should I delete the rolling cache or reinstall MSFS?
Deleting the rolling cache is not a normal fix for “Error preparing navigation data” because that cache stores streamed scenery rather than the compiled navigation database. It may help a separate scenery-streaming fault, but it should not replace the Community-folder test or index rebuild.
A complete reinstall is justified only when the clean simulator still fails, the packages path is writable, and repair or verification cannot restore the official content. If repairing MSFS turns the problem into a download loop, decompression failure or missing-package message, use our package-update troubleshooting sequence before downloading the entire simulator again.