I was having an issue with the Nav III GPS turning on an telling me I had maps that were over a year old, when I had upgraded from 2009 City Navigator to 2010 and was using the online downloads from my Mac.
Well, it turned out the problem was between the chair and the keyboard.
Garmin has produced a number of tools for the Mac and they all run on OS/X Snow Leopard. They Include Base Camp, MapInstal, MapManager, RoadTrip and WebUpdater. I have mentioned before that Apple tools transfer data faster to my Nav III than WIndows XP did. But I had this nagging problem with out of date map warnings, and I was sure I had upgraded to 2010.
I looked harder at the menu in Garmin MapInstall, and saw that if I expanded the menu line, I had both
City Navigator North America NT 2009 and
City Navigator North America NT 2010-2
So I checked both and found that all the state/area maps that I had on the Nav III were still from the 2009 map and the 2010 map was blank. I went back to the 2009 map, clicked off all the maps and then switched to the 2010-2 menu map and added all the maps going back and forth to Redmond, OR.
I have not seen the out of date warning yet, and a yes, a few streets actually work now.