I have 2 Gamin Quest units. I have tried to load a newer map version on the Quests, but I received the "Can't unlock maps" messages. I have reset both units to the factory default settings, but seems to be doing something wrong, as I keep on getting the same message. I am able to see the US maps, but even if I select a different map in the Map Info dialogue box, I am not able to see the selected map. I am aware that the Quest is still working with Non-NT maps. How do I delete an installed map and how or up to which map version may I load onto the Quest units. I realize these are older units, but they must still be able to work with some map version.