I have a Nuvi 265 W and a Mac, I downloaded rar file for North America 2011 opened and I have 3 IMG files: gmap3d,GMASUPP,and gmaptz Listed as NDIF Disk Image for all 3 of them, size: 153.9Mb, 1.24 GB, 588Kb respectably, I am sorry I am totally new and going on a trip to Florida... I tried to read as much and downloaded Jetmouse but for the life of me I don't know where to begin...I tried to replace the same name files with the new ones in the Library-Gamin-Maps but I backed out from fear. yes I have a condition like charlie sheen... any help would be greatly appreciated to update the maps. Cheers