What causes "Theme switching is unsuccessful: {result}" in AutoDarkMode/Windows-Auto-Night-Mode?

Ensure no other tool is applying theme/personalization changes simultaneously.

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

Theme switching is unsuccessful: {result}

Error message

Theme switching is unsuccessful: {result}

What it means

Same RequestThemeSwitch pattern in ThemePickerViewModel. Thrown when Command.RequestSwitch reply != Ok; Source='ThemePickerViewModel'. Called after color/ignore-color settings are written. Caught locally and routed to ShowErrorMessage.

Source

Thrown at AutoDarkModeApp/ViewModels/ThemePickerViewModel.cs:238

    partial void OnIgnoreDesktopIconsEnabledChanged(bool value)
    {
        WriteSettings();
    }

    partial void OnIgnoreColorEnabledChanged(bool value)
    {
        WriteSettings();
    }

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

}

View on GitHub (pinned to c15b28e921)

Solutions

Ensure no other tool is applying theme/personalization changes simultaneously.
Verify the service is running and review its log.
Retry the switch.
Confirm the 15s timeout is not being exceeded on slow systems.

Defensive patterns

Strategy: try-catch

Validate before calling

// Verify accent color / theme settings are coherent before switching
public static bool AccentSettingsValid(AdmConfigBuilder b) =>
    b.Config.AutoThemeSwitchingEnabled;

Try / catch

// Already caught locally. Refactor to Task-returning if observability needed.
try { await RequestThemeSwitchAsync(); }
catch (SwitchThemeException ex) { /* log ex.Source */ }

Prevention

Ensure no other personalization tool is changing the accent/theme concurrently.
Debounce OnIgnoreColorEnabledChanged so rapid toggles do not stack switches.
Confirm the service is running before the picker page loads.
Review the service log on persistent non-Ok replies.

When it happens

Trigger: ThemePickerViewModel.RequestThemeSwitch() runs after an accent/ignore-color setting change (e.g. OnIgnoreColorEnabledChanged -> WriteSettings -> RequestThemeSwitch). Reply != 'Ok'.

Common situations: Accent color or theme application failed in the service; service busy; timeout; conflicting personalization tools holding registry locks.

Related errors

AI-assisted analysis of AutoDarkMode/Windows-Auto-Night-Mode@c15b28e921 (2026-08-13). Data as JSON: /api/errors/23148ea84bbae8e0. Report an issue: GitHub.