I have 08 denali i recently purchased updated software disk. Its not responding to new disk or old disk. I put disk in and it says insert disk!

Are you talking about a navigation disk? If so you have to go into the nav menu using the soft buttons to get the face of the radio to pop away from the dash. There is a 2nd slot behind the radio face for the nav disc. The top slot on the outside is for Cd's only.

I put it in 2nd slot. No response. What should happen when I insert disk. How do I get it to respond

Did you close the face of the radio by pushing it firmly closed?

If so it should load and read the disc in a matter of a few minutes. Are you sure you have the correct nav disc for the 08 GM trucks?

I do. The weird part is the nav disk that has been in there for years is not responding. Neither disk old or new. Any tricks?

Is the truck very cold? Its 14 here with a wind chill of -1. It will mess with electronics until it warms up.

It 60• I'm in La. I guess I'll keep trying it. Thanks for your suggestions. If anything comes to mind please let me know.

Well I guess cold is not a problem then, LOL. You could try unhooking the battery for a few minutes, hook it back up then try the nav again. Otherwise you have a problem with the head unit (stereo/nav/DVD player. Have it looked at by a reputable mechanic.