I updated my Garmin Zumo XT, and it showed me the error "map data not available" when I wanted to search for an address. There are a number of threads online, but my solution was not to do a reset or something. Instead, I downloaded Garmin Express (on my Mac), hooked up the Zumo XT and refreshed the maps through the application. I hope this helps people because the Garmin Support pages are not easy to read.