diff --git a/Packages/net.fushizen.modular-avatar/Editor/BoneProxyHook.cs b/Packages/net.fushizen.modular-avatar/Editor/BoneProxyHook.cs
index ca6a910f..20a103af 100644
--- a/Packages/net.fushizen.modular-avatar/Editor/BoneProxyHook.cs
+++ b/Packages/net.fushizen.modular-avatar/Editor/BoneProxyHook.cs
@@ -22,6 +22,7 @@
  * SOFTWARE.
  */
 
+using UnityEditor;
 using UnityEngine;
 using VRC.SDKBase.Editor.BuildPipeline;
 
@@ -37,7 +38,10 @@ namespace net.fushizen.modular_avatar.core.editor
 
             foreach (var proxy in boneProxies)
             {
-                if (proxy.constraint != null) UnityEngine.Object.DestroyImmediate(proxy.constraint);
+                if (proxy.constraint != null && proxy.constraint.gameObject == proxy.gameObject)
+                {
+                    UnityEngine.Object.DestroyImmediate(proxy.constraint);
+                }
                 if (proxy.target != null)
                 {
                     var oldPath = RuntimeUtil.AvatarRootPath(proxy.gameObject);