Running installer from File Explorer doesn't work, cmd line does

This is "odd". I DL'ed an installer "GeminiTelescopeInstaller(1.1.13.0).exe" to a folder, and in File Explorer I double clicked it. Mouse pointer changed to busy for a short while then nothing.

Now navigate to same folder in command line prompt and run the installer - got UAC prompt and after agreement, the installer runs!

FULL disclosure if relevant. I am running Explorer Patcher.
Any clues?
Thanks, David

Hmmm Needed to "Unblock" the exe and then it would install from Explorer - I thought this was supposed to cause a prompt saying "Windows has blocked access ..."