title: Exception At the start up of the android application in Xamarin
body: <p>I am new to Android Development in Xamarin. I have created a sample application and it was running fine. But suddenly i got the below error which i am not able to figure out what to do. I did not get any solution from internet. I have reinstalled everything but no luck. Please help!</p>
  
  <ul>
  <li>Java JDK 1.7.0 </li>
  <li>Android SDK 22.0.0 </li>
  <li>GTK# 2.12.26  </li>
  <li>Xamarin Studio 5.9.4 </li>
  <li>Xamarin 3.11.666</li>
  </ul>
  
  <p>Error:</p>
  
  <pre><code>Java.Lang.RuntimeException: java.lang.reflect.InvocationTargetException
    at --- End of managed exception stack trace ---
    at java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
    at at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
    at at dalvik.system.NativeStart.main(Native Method)
    at Caused by: java.lang.reflect.InvocationTargetException
    at at java.lang.reflect.Method.invokeNative(Native Method)
    at at java.lang.reflect.Method.invoke(Method.java:515)
    at at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
    at ... 2 more
    at Caused by: md52ce486a14f4bcd95899665e9d932190b.JavaProxyThrowable: System.ArgumentNullException: Argument cannot be null.
    at Parameter name: value
    at at Newtonsoft.Json.Utilities.ValidationUtils.ArgumentNotNull (object,string) &lt;IL 0x00009, 0x0006c&gt;
    at at Newtonsoft.Json.JsonConvert.DeserializeObject (string,System.Type,Newtonsoft.Json.JsonSerializerSettings) &lt;IL 0x00006, 0x00067&gt;
    at at Newtonsoft.Json.JsonConvert.DeserializeObject&lt;Tasky.Core.UserData&gt; (string,Newtonsoft.Json.JsonSerializerSettings) &lt;0x00063&gt;
    at at Newtonsoft.Json.JsonConvert.DeserializeObject&lt;Tasky.Core.UserData&gt; (string) &lt;0x0006b&gt;
    at TaskyAndroid.Screens.HomeScreen.OnCreate (Android.OS.Bundle) [0x00017] in f:\Solutions\Xamarin\Tasky\Android_Starter\TaskyAndroid\Screens\HomeScreen.cs:60
    at Android.App.Activity.n_OnCreate_Landroid_os_Bundle_ (intptr,intptr,intptr) [0x00011] in /Users/builder/data/lanes/1879/5f55a9ef/source/monodroid/src/Mono.Android/platforms/android-10/src/generated/Android.App.Activity.cs:1777
    at at (wrapper dynamic-method) object.6147fbee-1dc5-4093-b962-ef4f61496551 (intptr,intptr,intptr) &lt;IL 0x00017, 0x00043&gt;
    at at md5b8e170d2a8045dd039dc8ae8a9f57934.HomeScreen.n_onCreate(Native Method)
    at at md5b8e170d2a8045dd039dc8ae8a9f57934.HomeScreen.onCreate(HomeScreen.java:29)
    at at android.app.Activity.performCreate(Activity.java:5231)
    at at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
    at at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148)
    at at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
    at at android.app.ActivityThread.access$800(ActivityThread.java:135)
    at at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
    at at android.os.Handler.dispatchMessage(Handler.java:102)
    at at android.os.Looper.loop(Looper.java:136)
    at at android.app.ActivityThread.main(ActivityThread.java:5001)
    at ... 5 more
  </code></pre>