Can someone answer if maps are loaded on the SD card if they will interfere with the internal maps? I have a 2597LMT and loaded maps for France/Spain/UK/Morocco etc onto the SD card which were originally downloaded from openstreetmap. Things seemed OK at first but then the Nuvi would recalculate at seemingly random times. It also stopped giving me vocal directions or showing speed limits and the lane guidance stopped working. I then bought a Drivesmart 6.95 but found it had similar problems... Being suspicious I recently had them both mounted for a trip from Brittany France to near Amsterdam NL. Driving North up through France I realised that they were not recalculating randomly, but doing it at the same time! Further North in France and then through Belgium and NL they stopped recalculating, and both started working perfectly normally with speed limits, vocal directions and lane guidances! The only common factor I can figure out is either the maps loaded on the SD are interferring with the normal functioning of both satnavs, or there is something wrong with the Garmin map updates which are being downloaded (via Garmin Express for the 2597 or via the built-in wifi on the Drivesmart 695). It wouyold be nice to know which for sure.