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"Cannot Authenticate Maps" Error Message on a Compatible Garmin Watch
If a Garmin® watch displays the message Cannot Unlock Maps or Cannot Authenticate Maps, it has detected a map that cannot be validated for use with that device.
This Can be Caused By:
A problem with the data in the map file
Incorrect or missing unlock information for an installed map
To Resolve These Issues:
If maps have not been installed or updated recently, update the maps using Garmin Express™ software.
If the issue occurred as a result of updating the maps, ensure that the Garmin Express program is up to date, then reinstall the maps. For instructions, see - Reinstalling TopoActive, CourseView, and Ski Maps to an Outdoor Watch. Be sure to use the Safely Remove Hardware option on a Windows computer, or the Eject Device option on a Mac, after the update has completed. Even though the update appears to complete, the write-caching feature on some computers may have not have completely built or transferred the map to the device. Ejecting the device before disconnecting it can prevent this error. To eject the device:
Windows: Press the Windows key + E, Right-click the Garmin device, and choose Eject (if the device is not listed it does not need to be ejected).
Mac: Drag the device to the trash or open the Finder and choose the Eject symbol next to the Garmin device (if the device is not listed it does not need to be ejected).
The Garmin watch should now power on without displaying the error message.