I am not sure what you are getting at with the question. But the answer is yes and yes. The DVD map disc has to be in the Nav system for it to work. But it is a separate slot behind the screen, and a music CD or movie DVD goes in the upper front slot, so yes you can listen to a CD or watch a DVD movie and still use the NAV.
I bought my Enclave back in April. I don't know if GM is doing a better job now of explaining all of the entertainment options but I know back then there was very little desciption of how many slots came with each option.
Just started fooling with my NAV system in the driveway , and can't figure out how to operate the NAV system without the radio being on. I'm sure the explantion is simple , but i can't find it. Any help would be appreciated.
Apparently it's not just a Lambda thing...a family member has an '08 DTS and the nav won't work without the radio being on. Really gotta wonder what they were thinking on that one. FWIW, the nav in both cars looks like it came from the same parts bin.