diff --git a/Assets/UniGLTF/Runtime/UniHumanoid/AvatarDescription.cs b/Assets/UniGLTF/Runtime/UniHumanoid/AvatarDescription.cs
index 05dd9bdf0..496db8baf 100644
--- a/Assets/UniGLTF/Runtime/UniHumanoid/AvatarDescription.cs
+++ b/Assets/UniGLTF/Runtime/UniHumanoid/AvatarDescription.cs
@@ -98,7 +98,9 @@ namespace UniHumanoid
             {
                 map[t.name] = t;
             }
-            return human.Select(x => (map[x.boneName], x.humanBone));
+            return human
+                .Where(x => !string.IsNullOrEmpty(x.boneName) && map.ContainsKey(x.boneName))
+                .Select(x => (map[x.boneName], x.humanBone));
         }
 
         public Avatar CreateAvatarAndSetup(Transform root)
diff --git a/Assets/VRM10/Runtime/IO/Vrm10Importer.cs b/Assets/VRM10/Runtime/IO/Vrm10Importer.cs
index 3c28d48e2..af6bdc9c1 100644
--- a/Assets/VRM10/Runtime/IO/Vrm10Importer.cs
+++ b/Assets/VRM10/Runtime/IO/Vrm10Importer.cs
@@ -590,7 +590,10 @@ namespace UniVRM10
 
                     if (gltfSpring.ColliderGroups != null)
                     {
-                        spring.ColliderGroups = gltfSpring.ColliderGroups.Select(x => controller.SpringBone.ColliderGroups[x]).ToList();
+                        spring.ColliderGroups = gltfSpring.ColliderGroups
+                            // VRM1_Constraint_Twist_Sample_Plane.vrm
+                            .Where(x => x >= 0 && x < controller.SpringBone.ColliderGroups.Count)
+                            .Select(x => controller.SpringBone.ColliderGroups[x]).ToList();
                     }
                     // joint
                     foreach (var gltfJoint in gltfSpring.Joints)