diff --git a/Assets/UniGLTF/Editor/UniGLTF/ExportDialog/SaveFileDialog.cs b/Assets/UniGLTF/Editor/UniGLTF/ExportDialog/SaveFileDialog.cs
index 793a7868e..b820a39f2 100644
--- a/Assets/UniGLTF/Editor/UniGLTF/ExportDialog/SaveFileDialog.cs
+++ b/Assets/UniGLTF/Editor/UniGLTF/ExportDialog/SaveFileDialog.cs
@@ -7,6 +7,18 @@ namespace UniGLTF
     public static class SaveFileDialog
     {
         static string m_lastExportDir;
+
+        static string extensionString(string[] extensions)
+        {
+#if UNITY_EDITOR_OSX
+            // in OSX multi extension cause exception.
+            // https://github.com/vrm-c/UniVRM/issues/1837
+            return extensions.Length > 0 ? extensions[0] : "";
+#else
+            return string.Join(",", extensions);
+#endif
+        }
+
         public static string GetPath(string title, string name, params string[] extensions)
         {
             string directory = m_lastExportDir;
@@ -15,7 +27,7 @@ namespace UniGLTF
                 directory = Directory.GetParent(Application.dataPath).ToString();
             }
 
-            var path = EditorUtility.SaveFilePanel(title, directory, name, string.Join(",", extensions));
+            var path = EditorUtility.SaveFilePanel(title, directory, name, extensionString(extensions));
             if (!string.IsNullOrEmpty(path))
             {
                 m_lastExportDir = Path.GetDirectoryName(path).Replace("\\", "/");