2009 CLK550 top won't go down all the way
 

I'm a regular over on the Porsche forum, brand new here. I just inherited a 2009 CLK550 convertible. The top goes down until the last 2 inches or so. The rear cover won't slide into place to complete the process. The fluid reservoir in the trunk is right on the MIN line. Other than that, I don't know what to check.