title: Failed to start Watchman watch mode
body: <p>I am developing a React Native app. My code is error free, but it is facing build problems. I get an error in the Metro Bundler when I execute the command react-native run-android. The error says: </p>
  
  <pre><code>UnhandledPromiseRejectionWarning: Failed to start watch mode.
  </code></pre>
  
  <p>I also tried adding Watchman to node_modules using the command <code>$yarn</code> add watchman.
  I get a prompt that it is deprecated.</p>
  
  <p>How should I solve the error? </p>
  
  <p>My package.json contains the following:</p>
  
  <pre><code>"dependencies": {
      "expo": "^25.0.0",
      "native-base": "^2.3.7",
      "react": "16.2.0",
      "react-native": "0.52.0",
      "react-native-vector-icons": "^4.5.0",
      "react-navigation": "^1.0.0-beta.27",
      "watchman": "^1.0.0"
  }
  
  "devDependencies": {
      "babel-jest": "22.1.0",
      "babel-preset-react-native": "4.0.0",
      "jest": "22.1.3",
      "react-test-renderer": "16.2.0"
    }
  </code></pre>