BaseCamp Scanning GPS

When I connect my Zumo 595 (or any other Garmin I own) after the device mounts on the host filesystem BaseCamp spends several minutes scanning the GPS before it will let me download or upload. Says "device busy". What is it doing? Can I prevent this?

I am guessing BaseCamp is scanning/downloading map data from the device. This is curious because I have Garmin Express download new maps to both Mac and GPS so it should only take a moment to read the version off GPS map and off Mac map to see they are the same. Or supposed to be the same.