I was talking to Dave on Sunday morning at breakfast in Pinckney, and he though that it might have to do with the length of the route. He suggested cutting longer routes in half. I haven’t tested this myself. I use a Zumo 660 and haven’t gotten any errors as of yet. I use a lot of via points in my routes, set to no notification, and the longest trip I’ve used it on is from Pinckney to Chicago.