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

Verify all configured wallpaper file paths exist and are accessible.

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 WallpaperPickerViewModel. Thrown when Command.RequestSwitch reply != Ok; Source='WallpaperPickerViewModel'. Triggered after wallpaper switch settings change. Caught locally and shown via IErrorService.

Source

Thrown at AutoDarkModeApp/ViewModels/WallpaperPickerViewModel.cs:325

    private void HandleConfigUpdate(object sender, FileSystemEventArgs e)
    {
        StateUpdateHandler.StopConfigWatcher();
        _dispatcherQueue.TryEnqueue(() =>
        {
            _builder.Load();
            LoadSettings();
        });
        StateUpdateHandler.StartConfigWatcher();
    }

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

    partial void OnIsWallpaperSwitchEnabledChanged(bool value)
    {
        if (_isInitializing)
        {
            return;
        }

        _builder.Config.WallpaperSwitch.Enabled = value;

        SafeSaveBuilder();

View on GitHub (pinned to c15b28e921)

Solutions

Verify all configured wallpaper file paths exist and are accessible.
Ensure no other wallpaper-changing tool is running.
Check the service log for the wallpaper component error.
Retry the switch after confirming the service is responsive.

Defensive patterns

Strategy: try-catch

Validate before calling

// Validate every configured wallpaper path exists before requesting a switch
public static bool WallpaperPathsExist(AdmConfigBuilder b) =>
    b.Config.WallpaperSwitch.Component.Monitors.All(m => File.Exists(m.ThemeDarkPath) && File.Exists(m.ThemeLightPath));

Try / catch

// Already caught and routed to ShowErrorMessage. Refactor async void -> Task
// to let the caller observe the SwitchThemeException.

Prevention

Validate all wallpaper file paths in config exist and are readable.
Ensure no other wallpaper tool is active.
Stop the config watcher (StateUpdateHandler) before programmatic bulk changes to avoid concurrent switches.
Check the service log for the wallpaper component error.

When it happens

Trigger: WallpaperPickerViewModel.RequestThemeSwitch() runs after a wallpaper setting change (config watcher reload also calls LoadSettings). Reply to RequestSwitch (15s) != 'Ok'.

Common situations: Wallpaper file path is invalid/missing; the wallpaper component in the service failed; another process holds the wallpaper file; service timeout or unreachable.

Related errors

AI-assisted analysis of AutoDarkMode/Windows-Auto-Night-Mode@c15b28e921 (2026-08-13). Data as JSON: /api/errors/68d191fd53993f8d. Report an issue: GitHub.