ReactNative Error Command failed: xcrun instruments -s

For one of my "pet projects" (more on that in a lter post...) I am building a native a pp using ReactNative. After reinstalling MacOS on a brand new (and insanely fast) SSD drive I experienced the following error when starting up a ReactNative app in the simulator using the command react-native run-ios The error appearing was: react-native run-ios Scanning folders for symlinks in /projects/rn/tst1/node_modules (22ms) Found Xcode project tst1.xcodeproj xcrun: error: unable to find utility "instruments", not a developer tool or in PATH Command failed: xcrun instruments -s xcrun: error: unable to find utility "instruments", not a developer tool or in PATH The issue and solution is explained here: https://stackoverflow.com/questions/39778607/error-running-react-native-app-from-terminal-ios In the XCode Preferences you have to set the XCode Command Line Tool version: