MacOS app does not run on the Xcode simulator

I had a similar problem with Xcode 4.5.2.

To fix it I had to go to the menu Product > Edit Scheme... > Select "Run " (in the sidebar) > Info (tab). In here is a drop down box labeled Executable, select it and choose your app that you wish to launch when the Run button is clicked.

I had the same issue in late 2017 with Xcode 9.2.

I had to uncheck 'Debug Executable' and then my app was able to both run and stop.

You can open the settings by clicking Product -> Scheme -> Edit Scheme...

Simple

Select the desired active scheme and device/simulator from the toolbar (next to the "play" and "stop" buttons).

The scheme selection should look something like below where the name is that of the appropriate target.

I messed up my settings and had this same issue - builds the app but doesn't launch (either in the simulator or the device).

The answer Product > Edit Scheme got me half way there - then choose Run {your app} on the left. There is a launch Automatically radio button to check: