title: The "XamlCTask" task failed unexpectedly on visual studio for xamarin
body: <p>When I am trying to run application on Xamarin on visual studio, I am getting error as mentioned below and not able to run the application on device or emulator:</p>
  
  <pre><code>The "XamlCTask" task failed unexpectedly.
  Microsoft.Cci.Pdb.PdbDebugException: Unknown custom metadata item kind: 6
     at Microsoft.Cci.Pdb.PdbFunction.ReadCustomMetadata(BitAccess bits)
     at Microsoft.Cci.Pdb.PdbFunction..ctor(ManProcSym proc, BitAccess bits)
     at Microsoft.Cci.Pdb.PdbFunction.LoadManagedFunctions(BitAccess bits, UInt32 limit, Boolean readStrings)
     at Microsoft.Cci.Pdb.PdbFile.LoadFuncsFromDbiModule(BitAccess bits, DbiModuleInfo info, IntHashTable names, ArrayList funcList, Boolean readStrings, MsfDirectory dir, Dictionary`2 nameIndex, PdbReader reader)
     at Microsoft.Cci.Pdb.PdbFile.LoadFunctions(Stream read, Dictionary`2&amp; tokenToSourceMapping, String&amp; sourceServerData)
     at Mono.Cecil.Pdb.PdbReader.PopulateFunctions()
     at Mono.Cecil.Pdb.PdbReader.ProcessDebugHeader(ImageDebugDirectory directory, Byte[] header)
     at Mono.Cecil.ModuleDefinition.ProcessDebugHeader()
     at Mono.Cecil.ModuleDefinition.ReadSymbols(ISymbolReader reader)
     at Mono.Cecil.ModuleReader.ReadSymbols(ModuleDefinition module, ReaderParameters parameters)
     at Mono.Cecil.ModuleReader.CreateModuleFrom(Image image, ReaderParameters parameters)
     at Mono.Cecil.ModuleDefinition.ReadModule(Stream stream, ReaderParameters parameters)
     at Mono.Cecil.ModuleDefinition.ReadModule(String fileName, ReaderParameters parameters)
     at Xamarin.Forms.Build.Tasks.XamlCTask.Compile()
     at Xamarin.Forms.Build.Tasks.XamlCTask.Execute()
     at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute()
     at Microsoft.Build.BackEnd.TaskBuilder.&lt;ExecuteInstantiatedTask&gt;d__1.MoveNext()  MyFirstProject      
  </code></pre>
  
  <p>Before adding this "Xamarin.Forms.Maps" NuGet package, my application working but as I have added this suddenly application stops running and getting error.</p>
  
  <p>Anybody could help me what causes this type of issue?</p>