Magellan GPS Update not working on 10.13.5

I have two different Magellan GPS units neither of which have ben successful in updating on my Mac. i'm currently running 10.13.5 on a Mid 2011 21.5" iMac. I am prompted to download the SmartGPSEco program but the program cannot locate any connected devices. I have used a friends PC in the past but that option is no longer viable since I've moved away. I like the Magellan 3045LM and am reasonably satisfied with the 9196T-LM, but am hamstrung by the lack of updates.

I suppose it is possible that Magellan is one of the old school companies that believes everyone owns and uses a PC instead of a Mac and have no plans to become compatible, although I thought that mindset went away long ago! I don't travel roads that are likely to have changed much over the years but I am aware of highways that have had their exit numbers redone and the Magellan is still showing he old numbers.