diff --git a/Scripts/Format/VRMImporterContext.cs b/Scripts/Format/VRMImporterContext.cs
index e73bcb11f..f84e28480 100644
--- a/Scripts/Format/VRMImporterContext.cs
+++ b/Scripts/Format/VRMImporterContext.cs
@@ -17,6 +17,20 @@ namespace VRM
         {
         }
 
+        public override bool IsOverwrite(UnityEngine.Object o)
+        {
+            if(o is BlendShapeAvatar)
+            {
+                return false;
+            }
+            if(o is BlendShapeClip)
+            {
+                return false;
+            }
+
+            return base.IsOverwrite(o);
+        }
+
         public override void Parse(string path, byte[] bytes)
         {
             var ext = Path.GetExtension(path).ToLower();
diff --git a/UniGLTF b/UniGLTF
index 415719191..a59f6438e 160000
--- a/UniGLTF
+++ b/UniGLTF
@@ -1 +1 @@
-Subproject commit 415719191b542a949929ae8b431ae83062559b35
+Subproject commit a59f6438ec560c356a9bbb1517d95877e85927f4