Each time I start up in my iMac I get the message that the elevation data is not accurate etc. I have downloaded the Global file into the Little Navmap files file the others, restarted, and yet I still get the same message. I have checked the online manual which seems to be written for a PC but from what I can see matches up to what I have done. I cannot find the place to elect use off line directory. I have checked where I can to verify the file is in the correct pace. What am I not doing right here? I would welcome any help.