diff --git a/src/BizHawk.Client.Common/movie/BasicMovieInfo.cs b/src/BizHawk.Client.Common/movie/BasicMovieInfo.cs
index 5d80346d1b..404794d389 100644
--- a/src/BizHawk.Client.Common/movie/BasicMovieInfo.cs
+++ b/src/BizHawk.Client.Common/movie/BasicMovieInfo.cs
@@ -71,7 +71,7 @@ namespace BizHawk.Client.Common
 					const decimal attosInSec = 1_000_000_000_000_000_000.0M;
 					var m = attosInSec;
 					m /= ulong.Parse(vsyncAttoStr);
-					return (double) m;
+					return checked((double) m);
 				}
 
 				return PlatformFrameRates.GetFrameRate(SystemID, IsPal);