diff --git a/demo/extractmesh.c b/demo/extractmesh.c
index d34a8a6..8468a42 100644
--- a/demo/extractmesh.c
+++ b/demo/extractmesh.c
@@ -21,8 +21,10 @@ void writemesh(const struct MeshHeader *mh,
     write(fn, (char*)(&h),         sizeof(struct Header));
     append(fn, (char*)(&newmh),    sizeof(struct MeshHeader));
 
-    struct BatchData * newBatches = malloc(newmh.numBatch * sizeof(struct BatchData));
+
+
     // batch data the same treatment.
+    struct BatchData * newBatches = malloc(newmh.numBatch * sizeof(struct BatchData));
     uint64_t previousBatch = 0;
     for (int i = 0; i < newmh.numBatch; i++) {
       newBatches[i] = (m -> b) -> bd[i];
@@ -51,6 +53,7 @@ void writemesh(const struct MeshHeader *mh,
       append(fn, (char*)(m -> b[i].vd.bw),        sizeof(struct BoneWeights) * nVertices);
     }
 
+    free(newBatches);
     free(fn);
 }