diff --git a/Scripts/BlendShape/BlendShapeClip.cs b/Scripts/BlendShape/BlendShapeClip.cs
index dcc7aa5f2..0bfc9119b 100644
--- a/Scripts/BlendShape/BlendShapeClip.cs
+++ b/Scripts/BlendShape/BlendShapeClip.cs
@@ -10,6 +10,11 @@ namespace VRM
         public String RelativePath;
         public int Index;
         public float Weight;
+
+        public override string ToString()
+        {
+            return string.Format("{0}[{1}]=>{2}", RelativePath, Index, Weight);
+        }
     }
 
     [Serializable]
diff --git a/Scripts/BlendShape/BlendShapeMerger.cs b/Scripts/BlendShape/BlendShapeMerger.cs
index 5e8cb4c24..1f45c82c8 100644
--- a/Scripts/BlendShape/BlendShapeMerger.cs
+++ b/Scripts/BlendShape/BlendShapeMerger.cs
@@ -62,10 +62,18 @@ namespace VRM
                         }
                         if (target != null)
                         {
-                            m_blendShapeSetterMap.Add(binding, x =>
+                            if (binding.Index >= 0 && binding.Index < target.sharedMesh.blendShapeCount)
+                            {
+                                m_blendShapeSetterMap.Add(binding, x =>
                                 {
                                     target.SetBlendShapeWeight(binding.Index, x);
                                 });
+                            }
+                            else
+                            {
+                                Debug.LogWarningFormat("Invalid blendshape binding: {0}: {1}", target.name, binding);
+                            }
+
                         }
                         else
                         {
diff --git a/Scripts/BlendShape/MeshPreviewItem.cs b/Scripts/BlendShape/MeshPreviewItem.cs
index ffcce8fd0..be9293aa1 100644
--- a/Scripts/BlendShape/MeshPreviewItem.cs
+++ b/Scripts/BlendShape/MeshPreviewItem.cs
@@ -147,7 +147,17 @@ namespace VRM
                 {
                     if (x.RelativePath == Path)
                     {
-                        SkinnedMeshRenderer.SetBlendShapeWeight(x.Index, x.Weight * weight);
+                        if(x.Index>=0 && x.Index < SkinnedMeshRenderer.sharedMesh.blendShapeCount)
+                        {
+                            SkinnedMeshRenderer.SetBlendShapeWeight(x.Index, x.Weight * weight);
+                        }
+                        else
+                        {
+                            Debug.LogWarningFormat("Out of range {0}: 0 <= {1} < {2}", 
+                                SkinnedMeshRenderer.name, 
+                                x.Index, 
+                                SkinnedMeshRenderer.sharedMesh.blendShapeCount);
+                        }
                     }
                 }
             }
diff --git a/UniGLTF b/UniGLTF
index 03a4b678f..00452b9dc 160000
--- a/UniGLTF
+++ b/UniGLTF
@@ -1 +1 @@
-Subproject commit 03a4b678fc4e00cbb69e75cf56a2e46b72546b7f
+Subproject commit 00452b9dc8c87e10ce9405e8836b08a9d1243a8b