diff --git a/AssetStudio/Classes/AnimationClip.cs b/AssetStudio/Classes/AnimationClip.cs
index 29b26fa..c0aa4d6 100644
--- a/AssetStudio/Classes/AnimationClip.cs
+++ b/AssetStudio/Classes/AnimationClip.cs
@@ -1690,7 +1690,7 @@ namespace AssetStudio
                         m_MuscleClipSize = reader.ReadUInt32();
                         m_MuscleClip = ClipMuscleConstant.ParseGI(reader);
                     }
-                    else
+                    else if (muscleClipSize > 0)
                     {
                         m_MuscleClipSize = (uint)muscleClipSize;
                         m_MuscleClip = new ClipMuscleConstant(reader);
diff --git a/AssetStudioCLI/Exporter.cs b/AssetStudioCLI/Exporter.cs
index b684669..e92e95b 100644
--- a/AssetStudioCLI/Exporter.cs
+++ b/AssetStudioCLI/Exporter.cs
@@ -322,6 +322,8 @@ namespace AssetStudioCLI
                 return false;
             var m_AnimationClip = (AnimationClip)item.Asset;
             var str = m_AnimationClip.Convert();
+            if (string.IsNullOrEmpty(str)) 
+                return false;
             File.WriteAllText(exportFullPath, str);
             return true;
         }
diff --git a/AssetStudioGUI/AssetStudioGUIForm.cs b/AssetStudioGUI/AssetStudioGUIForm.cs
index cd0188a..c4cb9de 100644
--- a/AssetStudioGUI/AssetStudioGUIForm.cs
+++ b/AssetStudioGUI/AssetStudioGUIForm.cs
@@ -1292,6 +1292,8 @@ namespace AssetStudioGUI
         private void PreviewAnimationClip(AnimationClip clip)
         {
             var str = clip.Convert();
+            if (string.IsNullOrEmpty(str))
+                str = "Legacy animation is not supported";
             PreviewText(str.Replace("\n", "\r\n"));
         }
 
diff --git a/AssetStudioGUI/Exporter.cs b/AssetStudioGUI/Exporter.cs
index 9d758be..462efb5 100644
--- a/AssetStudioGUI/Exporter.cs
+++ b/AssetStudioGUI/Exporter.cs
@@ -321,6 +321,8 @@ namespace AssetStudioGUI
                 return false;
             var m_AnimationClip = (AnimationClip)item.Asset;
             var str = m_AnimationClip.Convert();
+            if (string.IsNullOrEmpty(str))
+                return false;
             File.WriteAllText(exportFullPath, str);
             return true;
         }
diff --git a/AssetStudioUtility/YAML/AnimationClipExtensions.cs b/AssetStudioUtility/YAML/AnimationClipExtensions.cs
index e4976b7..72ae180 100644
--- a/AssetStudioUtility/YAML/AnimationClipExtensions.cs
+++ b/AssetStudioUtility/YAML/AnimationClipExtensions.cs
@@ -144,6 +144,10 @@ namespace AssetStudio
         }
         public static string Convert(this AnimationClip clip)
         {
+            if (clip.m_Legacy || clip.m_MuscleClip == null)
+            {
+                return string.Empty;
+            }
             var converter = AnimationClipConverter.Process(clip);
             clip.m_RotationCurves = converter.Rotations.Union(clip.m_RotationCurves).ToArray();
             clip.m_EulerCurves = converter.Eulers.Union(clip.m_EulerCurves).ToArray();