diff --git a/Assets/UniGLTF/Editor/UniGLTF/ExportDialog/ExportDialogBase.cs b/Assets/UniGLTF/Editor/UniGLTF/ExportDialog/ExportDialogBase.cs
index 60c3c98ae..30034f70b 100644
--- a/Assets/UniGLTF/Editor/UniGLTF/ExportDialog/ExportDialogBase.cs
+++ b/Assets/UniGLTF/Editor/UniGLTF/ExportDialog/ExportDialogBase.cs
@@ -91,6 +91,10 @@ namespace UniGLTF
 
         protected abstract bool DoGUI();
 
+        protected virtual void OnLayout()
+        {
+        }
+
         bool BeginGUI()
         {
             // ArgumentException: Getting control 1's position in a group with only 1 controls when doing repaint Aborting
@@ -98,6 +102,7 @@ namespace UniGLTF
             // EventType.Layout と EventType.Repaint 間で内容が変わらないようしている。
             if (Event.current.type == EventType.Layout)
             {
+                OnLayout();
                 State.Validate(ValidatorFactory());
             }
 
diff --git a/Assets/VRM/Editor/Format/VRMExportMeshes.cs b/Assets/VRM/Editor/Format/VRMExportMeshes.cs
index e0f3202be..595161014 100644
--- a/Assets/VRM/Editor/Format/VRMExportMeshes.cs
+++ b/Assets/VRM/Editor/Format/VRMExportMeshes.cs
@@ -64,13 +64,15 @@ namespace VRM
         {
             VRMExportSettings = settings;
             Clips = new List<BlendShapeClip>();
-            var proxy = ExportRoot.GetComponent<VRMBlendShapeProxy>();
-            if (proxy != null)
+            if (ExportRoot != null)
             {
-                // Export サイズ の 計算
-                if (proxy.BlendShapeAvatar != null)
+                var proxy = ExportRoot.GetComponent<VRMBlendShapeProxy>();
+                if (proxy != null)
                 {
-                    Clips.AddRange(proxy.BlendShapeAvatar.Clips);
+                    if (proxy.BlendShapeAvatar != null)
+                    {
+                        Clips.AddRange(proxy.BlendShapeAvatar.Clips);
+                    }
                 }
             }
 
diff --git a/Assets/VRM/Editor/Format/VRMExporterWizard.cs b/Assets/VRM/Editor/Format/VRMExporterWizard.cs
index 1bb73b27a..12dc64bfb 100644
--- a/Assets/VRM/Editor/Format/VRMExporterWizard.cs
+++ b/Assets/VRM/Editor/Format/VRMExporterWizard.cs
@@ -160,6 +160,12 @@ namespace VRM
             VRMEditorExporter.Export(path, State.ExportRoot, Meta != null ? Meta : m_tmpMeta, m_settings, m_meshes.Meshes);
         }
 
+        protected override void OnLayout()
+        {
+            // m_settings, m_meshes.Meshes                
+            m_meshes.SetRoot(State.ExportRoot, m_settings);
+        }
+
         protected override bool DoGUI()
         {
             EditorGUILayout.HelpBox($"Mesh size: {m_meshes.ExpectedExportByteSize / 1000000.0f:0.0} MByte", MessageType.Info);