I have a 2007 SL550 w/18,000 miles. All of a sudden I can't get the top down with a "close trunk partition" comment on the dash. Never had an issue before.

First check the two switches on each side of the trunk where the luggage cover sits. If BOTH of those switches are not depressed - the trunk will not operate. Some people remove the luggage cover to get a little more space in the trunk when the top is up. That is fine, but you need to keep the two switches depressed. A small piece of wood or hard rubber works great fro this task since they will not fall out during driving vibrations.

I showed your response to the body shop that had replaced my passenger tail light. He said this led them to the switch that needed to be secured and fixed the problem!!! Thanks so much for you quick and proper response