diff --git a/packages/dev/core/src/Bones/skeleton.ts b/packages/dev/core/src/Bones/skeleton.ts
index ef1bdea9370..36b765fae9e 100644
--- a/packages/dev/core/src/Bones/skeleton.ts
+++ b/packages/dev/core/src/Bones/skeleton.ts
@@ -878,6 +878,8 @@ export class Skeleton implements IAnimatable {
         visited[index] = true;
 
         const bone = this.bones[index];
+        if (!bone) return;
+
         if (bone._index === undefined) {
             bone._index = index;
         }