diff --git a/osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmapConverter.cs b/osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmapConverter.cs
index 757329c525..7a0e3b2b76 100644
--- a/osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmapConverter.cs
+++ b/osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmapConverter.cs
@@ -28,7 +28,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps
         public bool Dual;
         public readonly bool IsForCurrentRuleset;
 
-        private int originalTargetColumns;
+        private readonly int originalTargetColumns;
 
         // Internal for testing purposes
         internal FastRandom Random { get; private set; }