This is the screen response under "Failed to open page": Safari can't open "tomtomhome:task:update" because OS X doesn't recognize internet addresses starting with tomtomhome.
This response followed linking the GPS device to the computer and requesting update of maps.
Since this a new iMac, I just downloaded TomTomHome. I must assume that the source carries the very latest. So, let's change to Chrome, although I don't like it . . .