diff --git a/BizHawk.Client.Common/movie/tasproj/TasStateManager.cs b/BizHawk.Client.Common/movie/tasproj/TasStateManager.cs
index e55cccfa33..0fa52ef981 100644
--- a/BizHawk.Client.Common/movie/tasproj/TasStateManager.cs
+++ b/BizHawk.Client.Common/movie/tasproj/TasStateManager.cs
@@ -58,7 +58,7 @@ namespace BizHawk.Client.Common
 
 			if (States.ContainsKey(frame))
 			{
-				States.Add(frame, state);
+				States[frame] = state;
 			}
 			else
 			{