I, also, do not have the nav system and the installation went fine. I sat in the car reading a magazine until the second Installation complete message was spoken. Took about 10 minutes altogether. Since it is a new version, as expected, I lost the bluetooth phone connections along with the phonebook. But that was not a hassle to re-link. I always get scared when it works the first time with a microsoft product! I figure they're planning an outrage! Peace! Rog