@StarshipKnight That's a generic error message when the compilation (and the follow-up installation) fails. You'll find the detailed error message in the ~/RetroPie-Setup/logs folder, in the most recent log file.

One last thing I am trying to do is have Kodi auto start on boot. The autostart option in RetrePie-Setup only lists enable/disable for ES autostart.

I edited .config/openbox/autostart and put gnome-terminal --full-screen --hide-menubar -- kodi-standalone #auto\nemulationstation #auto which I gleaned from https://github.com/RetroPie/RetroPie-Setup/blob/master/scriptmodules/supplementary/autostart.sh

Kodi will start, but when I exit, ES is not running or started.

Any ideas?

UPDATE: with help I figured it out

/home/pi/.config/openbox/autostart

gnome-terminal --full-screen --hide-menubar -- bash /home/pi/autostart.sh

and
/home/pi/autostart.sh (chmod +x)

#!/usr/bin/env bash kodi-standalone sleep 2 emulationstation