I normally don't autoroute anything, but I'd like to try it on a board I'm working on. Problem is this board is 8 layers and my seat is limited to 6 layers. I'm thinking I can remove the layers where I have the power and gnd planes from the stack up and disable those nets in CM. Then add the layers back in after the routing has been done.
If this will work, how do I "lock" any existing traces I have routed to prevent the autorouter from moving them?
You have your planes marked as PLANES in the stackup? Specctra doesn't count power planes against the 6 layer count.