When starting up KeyShot if you get an error about Python3 command needing developers tools. You can either install the tools by downloading them or you can turn off the option to use local Python 3 on your computer.

To Disable Python on your local machine go to the KeyShot preferences, then go to the General tab, scroll down to Scripting and uncheck Use local Python paths. 

To get to preferences you can go to 
Edit > Preferences

KeyShot > Preferences