Fix “Error Prepping Navigation Data” on Your GPS Fast (2026 Expert Guide)

⚡ Quick Answer: How to Fix the Error

• Reduce Waypoints: The route has too many turn-by-turn data points (over 50-100 limits for some devices). Simplify the route in Komoot or Strava.
• Clear Corrupt Files: Connect your device to a PC, open the Garmin/NewFiles and Garmin/Courses folders, and delete old or stuck GPX files.
• Change the File Format: Instead of syncing a .GPX or .TCX file, export your route as a .FIT file, which is natively optimized for modern GPS devices.
• Update Maps via Garmin Express: Ensure your device’s internal map data matches the map version used to create the route.

You are fully geared up for a long cycling route or a backcountry hike. You hit “Send to Device,” but instead of a successful sync, your screen flashes: “error prepping navigation data.”

This frustrating issue is incredibly common among Garmin Edge, Fenix, and Forerunner users, especially when importing third-party routes from platforms like Strava, RideWithGPS, or Komoot. The error essentially means your GPS device cannot mathematically process the route file you sent it. Below is an E-E-A-T verified, step-by-step guide to clearing this error and getting your navigation back on track.

Why Does the “Error Prepping Navigation Data” Occur?

To fix the problem permanently, it helps to understand why your device is rejecting the file. Modern navigation units process data differently than web-based mapping software.

4 Step-by-Step Solutions to Fix the Error

1. Simplify the Route (Reduce Waypoints)

If you are trying to sync a massive 150-mile gravel ride or a multi-day hiking trek, your GPS processor might simply be overwhelmed. You need to reduce the data points.

• Strava Users: Duplicate the route, edit it, and intentionally remove excess custom waypoints. Save and re-sync.
• Garmin Connect Users: Break the route into two separate courses (e.g., “Day 1 Part A” and “Day 1 Part B”).
• Disable Turn-by-Turn: In your device settings, go to Navigation > Courses > Saved Courses, select your route, and toggle off Turn Guidance. This stops the device from calculating every single curve.

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2. Clear the Corrupt “NewFiles” Folder

Often, the error prepping navigation data is caused by a digital logjam. An old, broken file is preventing new routes from compiling.

• Plug your Garmin or GPS device into your PC or Mac using a data-transfer USB cable.
• Open the device drive (it will appear as a USB mass storage drive).
• Navigate to the Garmin folder, then open the NewFiles folder.
• Delete everything inside the NewFiles folder (don’t worry, this only deletes pending uploads, not your history).
• Safely eject the device, restart it, and try sending the route again.

3. Export as a .FIT File Instead of .GPX

While GPX is the universal standard for map data, it is an older, bulkier XML format. Modern devices prefer .FIT (Flexible and Interoperable Data Transfer) files because they are incredibly compressed and less prone to compilation errors.

• Go to the third-party app where you created the route (RideWithGPS, Komoot).
• Click “Export” and choose FIT File (or TCX if FIT is unavailable).
• Manually drop this downloaded file directly into your device’s Garmin/NewFiles folder via USB.

4. Update Device Firmware and Maps

If your device’s basemap is drastically out of date, it will fail to “prep” the data because the trails on your imported route literally do not exist on the device’s internal map.

• Download and open Garmin Express on your desktop.
• Connect your device and click Check for Updates.
• Install any pending Map Updates and Software Updates. (Note: Map updates can take up to an hour depending on your internet speed).