Atari 800 - "Object reference not set to an instance of an object."

[CapnARRR]

Hi, I'm getting the following error message when trying to start a game in the Atari 800 platform.  Launchbox is working for all other system platforms, just the Atari 800 seems to be a problem:

Object reference not set to an instance of an object.

App:     LaunchBox
Version: 13.13
Theme:   Default
Type:    System.NullReferenceException
Site:    System.Object WriteCommonItem(System.Object)
Source:  LaunchBox

   at Unbroken.LaunchBox.Windows.Desktop.LaunchBoxAppSpecific.WriteCommonItem(Object )
   at Unbroken.LaunchBox.Windows.Desktop.LaunchBoxAppSpecific.ShowEmulatorNotConfiguredMessage(Game game, AdditionalApplication app)
   at Unbroken.LaunchBox.Windows.Desktop.ViewModels.GameDetailsViewModel.ValidateHttpPublisher(Object , Object , Object )
   at Unbroken.LaunchBox.Windows.Desktop.ViewModels.GameDetailsViewModel.MapTransactionalResolver()
   at Unbroken.LaunchBox.Windows.Desktop.Commands.ActionCommand.ReflectMetaIdentifier(Object )
   at Unbroken.LaunchBox.Windows.Desktop.Commands.ActionCommand.Execute(Object parameter)
   at MS.Internal.Commands.CommandHelpers.CriticalExecuteCommandSource(ICommandSource commandSource, Boolean userInitiated)
   at System.Windows.Controls.Button.OnClick()
   at System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e)
   at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
   at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   at System.Windows.UIElement.ReRaiseEventAs(DependencyObject sender, RoutedEventArgs args, RoutedEvent newEvent)
   at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
   at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
   at System.Windows.Input.InputManager.ProcessStagingArea()
   at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
   at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
   at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)

Recent Log:

   9:53:45 AM Exception

Retroarch alone seems to be running fine for the Atari800 games, so I don't think it's a retroarch issue, if that helps at all.

Thanks for your help!

Edited May 17 by CapnARRR

[C-Beats]

Still shouldn't throw an error like that but the stack trace makes it seem like your game doesn't actually have an emulator assigned to it and the app is trying to tell you as such.

[CapnARRR]

Thanks C-Beats, that did it.

For anyone else who ends up here, follow this:

highlight all games in the Atari 800 platform, used the bulk edit wizard to assign them to retroarch. 

Go to Tools, Manage, Emulators, highlight retroarch, edit, associated platforms, if "Atari 800" is not already in the list select the blank space at the bottom, add "Atari 800", select the atari800_libretro core and match the parameters for the other cores.