dotnet/maui · critical · InvalidOperationException

Unable to find Application Services

Error message

Unable to find Application Services

What it means

MauiCompatInitializer.Initialize runs during MAUI's hosted-services init on Windows. It resolves IDispatcher from the DI container, falling back to IPlatformApplication.Current?.Services; if neither is available it throws InvalidOperationException('Unable to find Application Services'). This signals the DI container is missing core MAUI services.

Solutions

1. Build the application through the standard MAUI host (CreateMauiApp/UseMauiApp) so IDispatcher and IPlatformApplication are registered.
2. If using a custom ServiceProvider, register IDispatcher and set IPlatformApplication.Current appropriately.
3. Ensure UseMauiCompatibility() is applied to the builder so initializers run in the right order.

Example fix

// before — custom host missing services
var services = new ServiceCollection();
var sp = services.BuildServiceProvider();
new MauiCompatInitializer().Initialize(sp); // throws
// after — use the MAUI host
var app = MauiApp.CreateMauiApp().UseMauiApp<App>().UseMauiCompatibility();

static IDispatcher ResolveDispatcher(IServiceProvider sp)
{
    var d = sp.GetService<IDispatcher>()
            ?? IPlatformApplication.Current?.Services?.GetService<IDispatcher>();
    if (d is null)
        throw new InvalidOperationException("Build the app via MauiApp.CreateMauiApp().UseMauiApp<T>() so IDispatcher is registered.");
    return d;
}

static bool HostProvidesDispatcher(IServiceProvider sp)
    => sp.GetService<IDispatcher>() is not null
       || IPlatformApplication.Current?.Services?.GetService<IDispatcher>() is not null;

When it happens

Trigger: IServiceProvider lacks IDispatcher AND IPlatformApplication.Current (or its Services) is null/unable to provide IDispatcher. Happens when the MAUI host was built without registering essential services or when the initializer runs in a context without the platform host.

Common situations: Calling compatibility APIs from a non-MAUI host (unit tests, a console host, design-time); a custom IServiceProvider not built via MauiApp/CreateMauiApp; DI registration order issue where MauiCompatInitializer runs before the dispatcher service is registered; partial setup where UseMauiApp<T>() was skipped.

Related errors

• Unable to find Application Services
• call Forms.Init() before this
• call GtkThemes.Init() before this
• ActivateApplication failed
• application

AI-assisted analysis of dotnet/maui@f377ff1c5e (2026-08-13). Data as JSON: /api/errors/fc0d7e52484bfe6f. Report an issue: GitHub.

Appendix: source

Thrown at src/Compatibility/Core/src/AppHostBuilderExtensions.cs:133

			return builder;
		}

		static MauiAppBuilder AddMauiCompat(this MauiAppBuilder builder)
		{
			builder.Services.TryAddEnumerable(ServiceDescriptor.Transient<IMauiInitializeService, MauiCompatInitializer>());
			return builder;
		}

		class MauiCompatInitializer : IMauiInitializeService
		{
			public void Initialize(IServiceProvider services)
			{
#if WINDOWS
				var dispatcher =
					services.GetService<IDispatcher>() ??
					IPlatformApplication.Current?.Services.GetRequiredService<IDispatcher>() ??
					throw new InvalidOperationException("Unable to find Application Services");

					dispatcher.DispatchIfRequired(() =>
					{
						var dictionaries = UI.Xaml.Application.Current?.Resources?.MergedDictionaries;
						if (UI.Xaml.Application.Current?.Resources != null && dictionaries != null)
						{
							// Microsoft.Maui.Controls.Compatibility
							UI.Xaml.Application.Current.Resources.AddLibraryResources("MicrosoftMauiControlsCompatibilityIncluded", "ms-appx:///Microsoft.Maui.Controls.Compatibility/Windows/Resources.xbf");
						}
					});
#endif
			}
		}
	}
}

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