diff --git a/DiscordChatExporter.Gui/App.axaml.cs b/DiscordChatExporter.Gui/App.axaml.cs
index 05eb9c05..a62e75b9 100644
--- a/DiscordChatExporter.Gui/App.axaml.cs
+++ b/DiscordChatExporter.Gui/App.axaml.cs
@@ -59,13 +59,9 @@ public class App : Application, IDisposable
                 {
                     RequestedThemeVariant = _settingsService.Theme switch
                     {
-                        ThemeVariant.System => Avalonia.Styling.ThemeVariant.Default,
                         ThemeVariant.Light => Avalonia.Styling.ThemeVariant.Light,
                         ThemeVariant.Dark => Avalonia.Styling.ThemeVariant.Dark,
-                        _
-                            => throw new InvalidOperationException(
-                                $"Unknown theme '{_settingsService.Theme}'."
-                            )
+                        _ => Avalonia.Styling.ThemeVariant.Default
                     };
 
                     InitializeTheme();
@@ -91,17 +87,13 @@ public class App : Application, IDisposable
         {
             "Light" => PlatformThemeVariant.Light,
             "Dark" => PlatformThemeVariant.Dark,
-            _ => PlatformSettings?.GetColorValues().ThemeVariant
+            _ => PlatformSettings?.GetColorValues().ThemeVariant ?? PlatformThemeVariant.Light
         };
 
-        this.LocateMaterialTheme<MaterialThemeBase>().CurrentTheme = actualTheme switch
-        {
-            PlatformThemeVariant.Light
-                => Theme.Create(Theme.Light, Color.Parse("#343838"), Color.Parse("#F9A825")),
-            PlatformThemeVariant.Dark
-                => Theme.Create(Theme.Dark, Color.Parse("#E8E8E8"), Color.Parse("#F9A825")),
-            _ => throw new InvalidOperationException($"Unknown theme '{actualTheme}'.")
-        };
+        this.LocateMaterialTheme<MaterialThemeBase>().CurrentTheme =
+            actualTheme == PlatformThemeVariant.Light
+                ? Theme.Create(Theme.Light, Color.Parse("#343838"), Color.Parse("#F9A825"))
+                : Theme.Create(Theme.Dark, Color.Parse("#E8E8E8"), Color.Parse("#F9A825"));
     }
 
     public override void OnFrameworkInitializationCompleted()