While going to build the .Driod project of Xamarin forms got "The "Javac" task failed unexpectedly"

Due to version conflict I did Uninstall and then Reinstall all of the NuGet Packages in .Droid and Portable project accordingly.
The version conflict error is gone but get 1 error :
[
The "Javac" task failed unexpectedly. System.UnauthorizedAccessException: Access to the path 'C:\Users\a585113\Documents\Visual Studio 2015\Projects\WeatherApp4\WeatherApp4\WeatherApp4.Droid\obj\Debug\android\src\mono\android\support\v7\internal' is denied.
at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
at System.IO.FileSystemEnumerableIterator1.AddSearchableDirsToStack(SearchData localSearchData) at System.IO.FileSystemEnumerableIterator1.MoveNext()
at System.Collections.Generic.List1..ctor(IEnumerable1 collection)
at System.IO.Directory.GetFiles(String path, String searchPattern, SearchOption searchOption)
at Xamarin.Android.Tasks.Javac.GenerateResponseFile()
at Xamarin.Android.Tasks.Javac.Execute()
at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute()
at Microsoft.Build.BackEnd.TaskBuilder.d__26.MoveNext()
]

How to resolve it?

Attached The Screen shot below, click on icon to check.