diff --git a/AssetStudioFBXWrapper/FbxExporterContext.cs b/AssetStudioFBXWrapper/FbxExporterContext.cs
index 8040d0c..d8fa9a4 100644
--- a/AssetStudioFBXWrapper/FbxExporterContext.cs
+++ b/AssetStudioFBXWrapper/FbxExporterContext.cs
@@ -228,19 +228,18 @@ namespace AssetStudio.FbxInterop
 
                     foreach (var bone in boneList)
                     {
+                        var cluster = IntPtr.Zero;
                         if (bone.Path != null)
                         {
                             var frame = rootFrame.FindFrameByPath(bone.Path);
-                            var boneNode = _frameToNode[frame];
 
-                            var cluster = AsFbxMeshCreateCluster(_pContext, boneNode);
-
-                            AsFbxMeshAddCluster(pClusterArray, cluster);
-                        }
-                        else
-                        {
-                            AsFbxMeshAddCluster(pClusterArray, IntPtr.Zero);
+                            if (frame != null)
+                            {
+                                var boneNode = _frameToNode[frame];
+                                cluster = AsFbxMeshCreateCluster(_pContext, boneNode);
+                            }
                         }
+                        AsFbxMeshAddCluster(pClusterArray, cluster);
                     }
                 }