diff --git a/src/Snap.Hutao/Snap.Hutao/Service/Game/LaunchOptions.cs b/src/Snap.Hutao/Snap.Hutao/Service/Game/LaunchOptions.cs
index 8863e5fb..4b614ef3 100644
--- a/src/Snap.Hutao/Snap.Hutao/Service/Game/LaunchOptions.cs
+++ b/src/Snap.Hutao/Snap.Hutao/Service/Game/LaunchOptions.cs
@@ -184,7 +184,7 @@ internal sealed class LaunchOptions : DbStoreOptions
 
             static int RestrictIndex(List<NameValue<int>> monitors, string index)
             {
-                return Math.Clamp(int.Parse(index, CultureInfo.InvariantCulture) - 1, 0, monitors.Count);
+                return Math.Clamp(int.Parse(index, CultureInfo.InvariantCulture) - 1, 0, monitors.Count - 1);
             }
         }