title: Xamarin.Forms iOS Project Failed to Resolve "System.Runtime.InteropServices.StandardOleMarshalObject"
body: <p>After updating to <em>Xcode 10.0</em> (on Mac) and <em>Xamarin.Forms v3.2.0.871581</em> (on Mac/PC), I am no longer able to successfully build my Forms.iOS project.</p>
  
  <p>Not only does it not successfully build, but often will attempt to deploy to the iPhoneSimulator just to fail when attempting to install the application on the sim.</p>
  
  <p>This is the error I am encountering:<br/>
  <code>Failed to resolve "System.Runtime.InteropServices.StandardOleMarshalObject" reference from "System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"</code></p>
  
  <p>Here is the full crash log output:</p>
  
  <pre><code>1&gt;------ Rebuild All started: Project: EISPocketJMS4.iOS, Configuration: Debug iPhoneSimulator ------
  1&gt;  Connecting to Mac server 192.168.1.165...
  1&gt;C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\Xamarin\Xamarin.Sdk.targets(66,3): warning MSB3491: Could not write lines to file "obj\iPhoneSimulator\Debug\\_TelemetryProps". Could not find a part of the path 'C:\Users\zach\Desktop\EISPocketJMS4_Solution\EISPocketJMS4\EISPocketJMS4.iOS\obj\iPhoneSimulator\Debug\_TelemetryProps'.
  1&gt;  Connecting to Mac server 192.168.1.165...
  1&gt;  No way to resolve conflict between "System.Numerics, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" and "System.Numerics, Version=2.0.5.0, Culture=neutral, PublicKeyToken=b77a5c561934e089". Choosing "System.Numerics, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" arbitrarily.
  1&gt;  No way to resolve conflict between "System.Runtime.Serialization, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" and "System.Runtime.Serialization, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e". Choosing "System.Runtime.Serialization, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" arbitrarily.
  1&gt;  Consider app.config remapping of assembly "System.Numerics, Culture=neutral, PublicKeyToken=b77a5c561934e089" from Version "2.0.5.0" [C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\Common7\IDE\ReferenceAssemblies\Microsoft\Framework\Xamarin.iOS\v1.0\System.Numerics.dll] to Version "4.0.0.0" [C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Numerics\v4.0_4.0.0.0__b77a5c561934e089\System.Numerics.dll] to solve conflict and get rid of warning.
  1&gt;C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\Microsoft.Common.CurrentVersion.targets(2110,5): warning MSB3276: Found conflicts between different versions of the same dependent assembly. Please set the "AutoGenerateBindingRedirects" property to true in the project file. For more information, see http://go.microsoft.com/fwlink/?LinkId=294190.
  1&gt;C:\Users\zach\Desktop\EISPocketJMS4_Solution\EISPocketJMS4\EISPocketJMS4\Globals.cs(124,40,124,59): warning CS1998: This async method lacks 'await' operators and will run synchronously. Consider using the 'await' operator to await non-blocking API calls, or 'await Task.Run(...)' to do CPU-bound work on a background thread.
  1&gt;  EISPocketJMS4.iOS -&gt; C:\Users\zach\Desktop\EISPocketJMS4_Solution\EISPocketJMS4\EISPocketJMS4.iOS\bin\iPhoneSimulator\Debug\EISPocketJMS4.iOS.exe
  1&gt;  Detected signing identity:
  1&gt;    Provisioning Profile: "iOS Team Provisioning Profile: *" ([removed for privacy])
  1&gt;    Bundle Id: com.eis.EISPocketJMS4
  1&gt;    App Id: DH32F99JXP.com.eis.EISPocketJMS4
  1&gt;C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(794,3): error MT2002: Failed to resolve "System.Runtime.InteropServices.StandardOleMarshalObject" reference from "System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
  ========== Rebuild All: 0 succeeded, 1 failed, 0 skipped ==========
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/bztkI.png" rel="nofollow noreferrer">Xamarin Simulator - Failed to install</a></p>
  
  <blockquote>
    <p><code>Failed to install //Users/ZachAibrary/Caches/Xamarin/mtbs/builds/EISPocketIMS4.iOS/1afdfObe9e0c1d15a5f8dfb4597 4398e/bin/iPhoneSimulator/Debug/EISPocketIMS4.i0S.app to 15C32787-E053AFCA-8598-D07E93B37640. Failed to launch the simulator. Could not find file "/Users/ZachAibrary/Caches/Xamarin/mtbs/builds/EISPocketiMS4.OS/1afdfObe9e0c1d15a5f8dfb45974398e/bin/iPhoneSimulator/Debug/EISPock etIMS4.i0S.app/EISPocketIMS4.i0S"</code></p>
  </blockquote>
  
  <p><br/>
  <strong>NOTE: I have tried both</strong> <strong><em>"Link Framework SDKs Only"</em></strong> <strong>and</strong> <strong><em>"Link All"</em></strong> <strong>Linking Behaviors.</strong></p>
  
  <p>I have been on this for nearing 2 days now, please help!</p>
  
  <p>Thanks</p>