I recently upgraded my Zumo 660 to a Zumo 590 and some routes and waypoints transferred over to the new GPS. I deleted all old .gpx files on my Win 10 PC, deleted all trips in trip planner on the device. The old routes and waypoints that are in internal storage are still there and cannot be deleted from BaseCamp. I assume the data has to be saved to a file somewhere.
Any help would be appreciated. Thanks in advance.