el capitan will not start download on macbook air

I started the El Capitan upgrade earlier today, but it aborted because of a shortage of disk space. I now have over 12Gb of free space.

When I go to the APP Store and click download, the little gear icon in the upper left just spins continuously.

I tried using the Upgrade Link in the "About this Mac" and it brings up the UPGRADES dialog of the APP Store. Then in the upper right corner I see [faintly] the word DOWNLOADED. But it is not an active link.

I'm thinking there is some file/switch somewhere that thinks I've successfully downloaded the code [and maybe I have] but I can't execute it.