AutoDarkMode/Windows-Auto-Night-Mode · warning · SwitchThemeException

Theme switching is unsuccessful: {result}

Error message

Theme switching is unsuccessful: {result}

What it means

Thrown by ColorizationViewModel.RequestThemeSwitch when the service reply to Command.RequestSwitch (with a 15-second timeout) is not StatusCode.Ok. SwitchThemeException formats the message as 'Theme switching is unsuccessful: {result}' where {result} is the raw status string returned. The method is async-void and already wraps everything in try/catch that routes to IErrorService.ShowErrorMessage.

Source

Thrown at AutoDarkModeApp/ViewModels/ColorizationViewModel.cs:71

        try
        {
            _skipConfigUpdate = true;
            _builder.Save();
        }
        catch (Exception ex)
        {
            _errorService.ShowErrorMessage(ex, App.MainWindow.Content.XamlRoot, "ColorizationViewModel");
        }
    }

    public async void RequestThemeSwitch()
    {
        try
        {
            var result = await MessageHandler.Client.SendMessageAndGetReplyAsync(Command.RequestSwitch, 15);
            if (result != StatusCode.Ok)
            {
                throw new SwitchThemeException(result, "ColorizationViewModel");
            }
        }
        catch (Exception ex)
        {
            await _errorService.ShowErrorMessage(ex, App.MainWindow.Content.XamlRoot, "ColorizationViewModel");
        }
    }

    public ColorizationViewModel(IErrorService errorService)
    {
        _dispatcherQueue = Microsoft.UI.Dispatching.DispatcherQueue.GetForCurrentThread();
        _errorService = errorService;

        try
        {
            _builder.Load();
        }
        catch (Exception ex)

View on GitHub (pinned to c15b28e921)

Solutions

  1. Check that AutoDarkModeSvc is running and responsive.
  2. Review the service log for the specific component that failed during the switch.
  3. Retry the theme switch after a brief delay (transient component lock).
  4. Increase or verify the 15-second timeout is sufficient for slow systems.
Defensive patterns

Strategy: try-catch

Validate before calling

// Best-effort pre-check that the service can switch before requesting
public static async Task<bool> CanSwitchAsync()
{
    try { var r = await MessageHandler.Client.SendMessageAndGetReplyAsync(Command.RequestSwitch, 15); return r == StatusCode.Ok; }
    catch { return false; }
}

Try / catch

// RequestThemeSwitch already catches and routes to _errorService.
// Callers need not wrap it (async-void), but should react to the error dialog.
// To make it observable, refactor to Task and await:
// private async Task RequestThemeSwitchAsync() { try {...} catch {...} }

Prevention

When it happens

Trigger: ColorizationViewModel.RequestThemeSwitch() is called (e.g. after a colorization setting change). SendMessageAndGetReplyAsync(Command.RequestSwitch, 15) returns a value != 'Ok' (e.g. 'Err', 'Timeout', or an error detail string). The exception is thrown and immediately caught by the surrounding catch.

Common situations: Service is busy or the theme switch component failed; the 15s timeout elapsed and the reply is 'Timeout'; the service returned an error detail because a sub-component (apps, wallpaper, system) failed to apply; service not running.

Related errors

AI-assisted analysis of AutoDarkMode/Windows-Auto-Night-Mode@c15b28e921 (2026-08-13). Data as JSON: /api/errors/acb285e4cc89e325. Report an issue: GitHub.