CosmosDB Quickstart Error

gistfile1.txt

    /Users/ian/Projects/DocumentDB-Quickstart-Xamarin/packages/Xamarin.Forms.2.3.3.180/build/portable-win+net45+wp80+win81+wpa81+MonoAndroid10+Xamarin.iOS10+xamarinmac20/Xamarin.Forms.targets(3,3): Error MSB4018: The "XamlCTask" task failed unexpectedly.
System.IO.FileNotFoundException: Could not find file "/Users/ian/Projects/DocumentDB-Quickstart-Xamarin/Droid/obj/Debug/DocumentDBTodo.Droid.dll.mdb".
File name: '/Users/ian/Projects/DocumentDB-Quickstart-Xamarin/Droid/obj/Debug/DocumentDBTodo.Droid.dll.mdb'


Server stack trace: 
  at System.IO.FileStream..ctor (System.String path, System.IO.FileMode mode, System.IO.FileAccess access, System.IO.FileShare share, System.Int32 bufferSize, System.Boolean anonymous, System.IO.FileOptions options) [0x00293] in /private/tmp/source-mono-2017-02/bockbuild-2017-02/profiles/mono-mac-xamarin/build-root/mono-x86/mcs/class/corlib/System.IO/FileStream.cs:282 
  at System.IO.FileStream..ctor (System.String path, System.IO.FileMode mode, System.IO.FileAccess access, System.IO.FileShare share, System.Int32 bufferSize, System.Boolean isAsync, System.Boolean anonymous) [0x00000] in /private/tmp/source-mono-2017-02/bockbuild-2017-02/profiles/mono-mac-xamarin/build-root/mono-x86/mcs/class/corlib/System.IO/FileStream.cs:149 
  at System.IO.FileStream..ctor (System.String path, System.IO.FileMode mode, System.IO.FileAccess access) [0x00000] in /private/tmp/source-mono-2017-02/bockbuild-2017-02/profiles/mono-mac-xamarin/build-root/mono-x86/mcs/class/corlib/System.IO/FileStream.cs:86 
  at (wrapper remoting-invoke-with-check) System.IO.FileStream:.ctor (string,System.IO.FileMode,System.IO.FileAccess)
  at Mono.CompilerServices.SymbolWriter.MonoSymbolFile.ReadSymbolFile (System.String mdbFilename) [0x00000] in <f812160bc1d54955ae9692ed601b6f12>:0 
  at Mono.CompilerServices.SymbolWriter.MonoSymbolFile.ReadSymbolFile (System.String mdbFilename, System.Guid assemblyGuid) [0x00000] in <f812160bc1d54955ae9692ed601b6f12>:0 
  at Mono.Cecil.Mdb.MdbReaderProvider.GetSymbolReader (Mono.Cecil.ModuleDefinition module, System.String fileName) [0x00012] in <f812160bc1d54955ae9692ed601b6f12>:0 
  at Mono.Cecil.ModuleReader.ReadSymbols (Mono.Cecil.ModuleDefinition module, Mono.Cecil.ReaderParameters parameters) [0x00032] in <d4dd94f3e5f74095b62543e88f18941d>:0 
  at Mono.Cecil.ModuleReader.CreateModuleFrom (Mono.Cecil.PE.Image image, Mono.Cecil.ReaderParameters parameters) [0x00042] in <d4dd94f3e5f74095b62543e88f18941d>:0 
  at Mono.Cecil.ModuleDefinition.ReadModule (System.IO.Stream stream, Mono.Cecil.ReaderParameters parameters) [0x00028] in <d4dd94f3e5f74095b62543e88f18941d>:0 
  at Mono.Cecil.ModuleDefinition.ReadModule (System.String fileName, Mono.Cecil.ReaderParameters parameters) [0x0000a] in <d4dd94f3e5f74095b62543e88f18941d>:0 
  at Mono.Cecil.AssemblyDefinition.ReadAssembly (System.String fileName, Mono.Cecil.ReaderParameters parameters) [0x00000] in <d4dd94f3e5f74095b62543e88f18941d>:0 
  at Xamarin.Forms.Build.Tasks.XamlCTask.Compile (System.Collections.Generic.IList`1[T] thrownExceptions) [0x001ca] in <1227cf7e606b494fb39e6f54ac85c90c>:0 
  at Xamarin.Forms.Build.Tasks.XamlCTask.Execute () [0x00007] in <1227cf7e606b494fb39e6f54ac85c90c>:0 
  at (wrapper xdomain-dispatch) Xamarin.Forms.Build.Tasks.XamlCTask:Execute (object,byte[]&,byte[]&)

Exception rethrown at [0]: 
  at (wrapper xdomain-invoke) Xamarin.Forms.Build.Tasks.XamlCTask:Execute ()
  at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute () [0x00023] in /private/tmp/source-mono-2017-02/bockbuild-2017-02/profiles/mono-mac-xamarin/build-root/msbuild-15.0/src/Build/BackEnd/TaskExecutionHost/TaskExecutionHost.cs:632 
  at Microsoft.Build.BackEnd.TaskBuilder+<ExecuteInstantiatedTask>d__26.MoveNext () [0x00249] in /private/tmp/source-mono-2017-02/bockbuild-2017-02/profiles/mono-mac-xamarin/build-root/msbuild-15.0/src/Build/BackEnd/Components/RequestBuilder/TaskBuilder.cs:787  (MSB4018) (DocumentDBTodo.Droid)