This is realllly basic but ever since I updated to V6 I can’t seem to get it. I had it with V5. I want to draw a closed polyline and then extrude it into a “solid”. The extrusion is always open on the ends the next time I use the Extrude Straight command. I could use the extrude surface command but that means I have a surface to keep track of and also make. I see the option to make solid in the Extrude Straight command but it does not carry over. 
Are you using the Extrude command from the Surface pull-down or the Solid pull-down?
They are the same command but there is a different command line option for this.
Ah that’s it, thanks. The icon is exactly the same for both.