I downloaded the new version of Mac OS X – “El Capitan” – but didn’t want to install it at the time. I was about to give an important talk and didn’t want it to get screwed up. Returning to the App Store later, I found that there was a record of having downloaded the update, but I could not proceed or start over. This problem is (as often) common enough to have two answers, one of which exposes the very interesting “Debug” menu of the App Store. You can delete all the old downloads and start again. But for me, this didn’t have an effect. I couldn’t get away from the grey spinning dial, and the icon “Downloaded”. However the solution was simple – the download was already in “Applications”. It’s called “Install Mac OS X El Capitan”.
A relief, and you may lay to that.
A further tip – one should move to a new version (0.39) and indeed new branch of Fink before updating.
Thanks to Stack Exchange for hosting these tips.