Почему в рабочем проекте вдруг возникла ошибка XamlParseException

Message="Вызов конструктора для типа "Wpf_3_PressADay.MainWindow", удовлетворяющего указанным ограничениям привязки, привел к выдаче исключения.": номер строки "3" и позиция в строке "9".
Source=PresentationFramework
LineNumber=3
LinePosition=9
StackTrace:
в System.Windows.Markup.XamlReader.RewrapException(Exception e, IXamlLineInfo lineInfo, Uri baseUri)
в System.Windows.Markup.WpfXamlLoader.Load(XamlReader xamlReader, IXamlObjectWriterFactory writerFactory, Boolean skipJournaledProperties, Object rootObject, XamlObjectWriterSettings settings, Uri baseUri)
в System.Windows.Markup.WpfXamlLoader.LoadBaml(XamlReader xamlReader, Boolean skipJournaledProperties, Object rootObject, XamlAccessLevel accessLevel, Uri baseUri)
в System.Windows.Markup.XamlReader.LoadBaml(Stream stream, ParserContext parserContext, Object parent, Boolean closeStream)
в System.Windows.Application.LoadBamlStreamWithSyncInfo(Stream stream, ParserContext pc)
в System.Windows.Application.LoadComponent(Uri resourceLocator, Boolean bSkipJournaledProperties)
в System.Windows.Application.DoStartup()
в System.Windows.Application.<.ctor>b__1(Object unused)
в System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
в MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
в System.Windows.Threading.DispatcherOperation.InvokeImpl()
в System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state)
в System.Threading.ExecutionContext.runTryCode(Object userData)
в System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup( TryCode code, CleanupCode backoutCode, Object userData)
в System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
в System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
в System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
в System.Windows.Threading.DispatcherOperation.Invoke()
в System.Windows.Threading.Dispatcher.ProcessQueue()
в System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
в MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
в MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
в System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
в MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
в System.Windows.Threading.Dispatcher.InvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
в MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
в MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
в System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
в System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
в System.Windows.Threading.Dispatcher.Run()
в System.Windows.Application.RunDispatcher(Object ignore)
в System.Windows.Application.RunInternal(Window window)
в System.Windows.Application.Run(Window window)
в System.Windows.Application.Run()
в Wpf_3_PressADay.App.Main() в C:\Users\Владимир\Desktop\Wpf_3_PressADay\Wpf_3_PressADay\obj\x86\Debug\App.g.cs :строка 0
в System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
в System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
в Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
в System.Threading.ThreadHelper.ThreadStart_Context(Object state)
в System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
в System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
в System.Threading.ThreadHelper.ThreadStart()
InnerException: System.IO.IOException
Message=Не удается найти ресурс "c".
Source=PresentationFramework
StackTrace:
в MS.Internal.AppModel.ResourcePart.GetStreamCore(FileMode mode, FileAccess access)
в System.IO.Packaging.PackagePart.GetStream(FileMode mode, FileAccess access)
в System.IO.Packaging.PackagePart.GetStream()
в System.Windows.Application.LoadComponent(Object component, Uri resourceLocator)
в Wpf_3_PressADay.MainWindow.InitializeComponent() в c:\Users\Владимир\Desktop\Wpf_3_PressADay\Wpf_3_PressADay\MainWindow.xaml:строка 1
в Wpf_3_PressADay.MainWindow..ctor() в C:\Users\Владимир\Desktop\Wpf_3_PressADay\Wpf_3_PressADay\MainWindow.xaml.cs:стр ока 36
InnerException: