Is this a bug report?

Yes

Have you read the Contributing Guidelines?

Yes

Environment

Environment:
OS: macOS Sierra 10.12.6
Node: 8.7.0
Yarn: 1.2.1
npm: 5.4.2
Watchman: 4.7.0
Xcode: Xcode 9.0 Build version 9A235
Android Studio: 2.3 AI-162.4069837

Packages: (wanted => installed)
react: 16.0.0-beta.5 => 16.0.0-beta.5
react-native: 0.49.3 => 0.49.3

Steps to Reproduce

Initing a new project works fine.

Expected Behavior

react-native run ios starts the application on the Simulator

Actual Behavior

react-native run ios starts the application on the Simulator, which crashes after splash screen, packager keeps running. Starting from XCode works.