title: Xamarin.Forms iOS build Can't resolve the reference 'System.Drawing.RectangleF'
body: <p>I have this error when building for Xamarin.Form.iOS</p>
  
  <pre><code>Can't resolve the reference 'System.Drawing.RectangleF', referenced from the method 'System.Void Xamarin.Forms.Platform.iOS.VisualElementTracker/&lt;&gt;c__DisplayClass29_0::&lt;OnUpdateNativeControl&gt;g__update|0()' in 'System.Drawing.Common, Version=4.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'.
  </code></pre>
  
  <p>and this is in output</p>
  
  <pre><code>Launch failed. The app 'MyApp.iOS' could not be launched on 'iPhone 6 iOS 12.0'. Error: error MT1008: Failed to launch the simulator: Could not find file "/Users/imac-nas01/Library/Caches/Xamarin/mtbs/builds/...
  </code></pre>
  
  <p>I dont know how to solve it, im using the last version of Xamarin Form and VS2017.</p>