Xojo can't find Xcode simulator

I installed Xcode 8.2 on my MacBook Pro running El Capitan 10.11.6 but it is on an external drive. Xcode will open and I can manually start the iOS simulator but Xojo 2016 Release 3 doesn’t list any simulators on the Build Settings -> iOS property “Simulator Device” and I cannot click on it. The run button is disabled as is the Build Application selection in the Project menu. This is true even after I manually run the simulation and have it open when I open Xojo.

How can explain to Xojo where to find the simulator?

Firstly, let’s find out the path that your system knows for Xcode.

xcode-select -p

Unless it knows about your externally (why?) installed Xcode, tell it the proper path with:

sudo xcode-select -s path_of_installation

For example, on my system:

sudo xcode-select -s /Applications/Xcode.app/Contents/Developer


Thanks so much @Gavin Smith, that did the trick! I installed the developer tools on an external drive because my startup disk is too full. :-\