I dont think Ive seen a thread on this specifically so sorry if its a repeat. Im a huge Noob on Basecamp so all is new to me. I bought a Nuvi 50LM (lifetime map updates) for the car last year and never installed an update till just a couple months ago. So on my desktop iMac I downloaded the update from the myGarmin page on the website to load onto the Nuvi. In the my maps page as I was selecting the download options, it shows an advanced button, I clicked this and it offered the option of downloading the map to the Device only/computer only/device and computer. I chose map and computer. after 2880mb download I have the full City Navigator 49 states on my Mac, with routes, POI's etc. I do not need to have my Garmin plugged in to bring up the map. It is on the computer. So I thought maybe this is a fluke, so today I plugged my Nuvi 50LM into my laptop and ran the same setup again, reinstalling the update onto the Nuvi, and AGAIN I have the full CN lower 49 loaded on to my laptop. When I plug in my Oregon, I can also load my changes on to it, I just view everything on the Oregons installed map when its plugged in. All the route/track/waypoint info appears to be a seperate database from the maps, so its all good. The advantage here is that I can play with routes, tracks, waypoints etc on the laptop or desktop without having to plug in the unit, then just load my changes onto the device next time I have it close. Or I can go over to my buddies house with the laptop and play with routes there. Its a happy little discovery for me. Hope it helps out someone else. This has been a great forum for learning this stuff.