diff --git a/Assets/VRM/Runtime/IO/VrmUtility.cs b/Assets/VRM/Runtime/IO/VrmUtility.cs
index a29f96762..22f2db8d5 100644
--- a/Assets/VRM/Runtime/IO/VrmUtility.cs
+++ b/Assets/VRM/Runtime/IO/VrmUtility.cs
@@ -22,6 +22,12 @@ namespace VRM
                 throw new FileNotFoundException(path);
             }
 
+            if (awaitCaller == null)
+            {
+                Debug.LogWarning("VrmUtility.LoadAsync: awaitCaller argument is null. ImmediateCaller is used as the default fallback. When playing, we recommend RuntimeOnlyAwaitCaller.");
+                awaitCaller = new ImmediateCaller();
+            }
+
             using (GltfData data = new AutoGltfFileParser(path).Parse())
             {
                 try