diff --git a/osu.Game/Online/API/Requests/DownloadBeatmapSetRequest.cs b/osu.Game/Online/API/Requests/DownloadBeatmapSetRequest.cs
index e8871bef05..2898955de7 100644
--- a/osu.Game/Online/API/Requests/DownloadBeatmapSetRequest.cs
+++ b/osu.Game/Online/API/Requests/DownloadBeatmapSetRequest.cs
@@ -23,6 +23,8 @@ namespace osu.Game.Online.API.Requests
             return req;
         }
 
+        protected override string FileExtension => ".osz";
+
         protected override string Target => $@"beatmapsets/{Model.OnlineBeatmapSetID}/download{(noVideo ? "?noVideo=1" : "")}";
     }
 }