I own two different Magellan GPS units, a 3045-LM and a 9616T-LM. I have been completely unsuccessful in getting updates to work properly using my iMac. At one point I had a friend with a PC who was willing to update them but we no longer live nearby and that option is gone. When I download the required program, the content manager, my computer cannot find the GPS units. I had read somewhere that Magellan was not supporting Apple for back ups, something I don't believe except for my personal experiences. Following all the directions on the content manager results in essentially a loop of open this close that download the other thing and when I go to where I should be I find myself back at the beginning of the loop. At no time do I see that the program has located the plugged in unit no matter which one I have tried to use. I reached out to Magellan several days ago but have yet to hear back anything beyond the automatic "Thank you for contacting us on your question" email. I've been frustrating myself on and off for over a year on this and decided to approach the forum for direction.