diff --git a/osu.Game/Rulesets/Edit/Checks/CheckMutedObjects.cs b/osu.Game/Rulesets/Edit/Checks/CheckMutedObjects.cs
index d755b5bba5..5b59a81f91 100644
--- a/osu.Game/Rulesets/Edit/Checks/CheckMutedObjects.cs
+++ b/osu.Game/Rulesets/Edit/Checks/CheckMutedObjects.cs
@@ -72,7 +72,7 @@ private IEnumerable<Issue> getVolumeIssues(HitObject hitObject, HitObject? sampl
             if (edgeType == EdgeType.None)
                 yield break;
 
-            string postfix = hitObject is IHasDuration ? edgeType.ToString().ToLowerInvariant() : null;
+            string postfix = hitObject is IHasDuration ? edgeType.ToString().ToLowerInvariant() : string.Empty;
 
             if (maxVolume <= muted_threshold)
             {