Solved: “Doh!” I must have been having a ‘Homer Moment’. I didn’t have ‘composite’ checked in Output → Post Processing.
I mixed an image with it’s AO pass in the compositor. Experimenting with exaggerating shadows for dramatic look. The compositor viewer shows the result but the cycles rendered image does not.
Screen grab for the comp image. Saved from the Rendering tab for rendered.
What am I doing wrong?
Update: I see that on the Render tab “composite” is not an option on the drop down menus. In another blend it is there and that shows the finished composited render. I don’t know how to get that back.