XAML designer crashed

hi all
another problem appear with my vs 2012
i lunched app success ,but when i closed it the xaml designer has been crashed




here detail :
UnauthorizedAccessException: Access to the path 'c:\users\hocine\documents\visual studio 2012\Projects\App38\App38\bin\Debug' is denied.
at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
  at System.IO.FileSystemEnumerableIterator`1.CommonInit()
  at System.IO.FileSystemEnumerableIterator`1..ctor(String path, String originalUserPath, String searchPattern, SearchOption searchOption, SearchResultHandler`1 resultHandler, Boolean checkHost)
  at System.IO.Directory.EnumerateFiles(String path, String searchPattern, SearchOption searchOption)
InnerException: None