diff --git a/src/trame_vtklocal/module/wasm.py b/src/trame_vtklocal/module/wasm.py
index bc94cc2..7be90f7 100644
--- a/src/trame_vtklocal/module/wasm.py
+++ b/src/trame_vtklocal/module/wasm.py
@@ -59,7 +59,10 @@ async def setup_wasm_directory(target_directory, wasm_url):
 
         # unpack
         with tarfile.open(dest_file) as tgz:
-            tgz.extractall(dest_folder)
+            if hasattr(tarfile, "data_filter"):
+                tgz.extractall(dest_folder, filter="data")
+            else:
+                tgz.extractall(dest_folder)
 
         print(f"Downloaded WASM:\n - from: {wasm_url}\n - to: {dest_folder}")
 
diff --git a/src/trame_vtklocal/utils/exporter.py b/src/trame_vtklocal/utils/exporter.py
index 5397e2f..67a36a3 100644
--- a/src/trame_vtklocal/utils/exporter.py
+++ b/src/trame_vtklocal/utils/exporter.py
@@ -330,7 +330,7 @@ def to_wazex(
             ),
         )
         # Write states
-        zipf.mkdir("states")
+        zipf.writestr("states/", "")
         for vtk_id in ids_to_export:
             zipf.writestr(
                 f"states/{vtk_id}",
@@ -338,7 +338,7 @@ def to_wazex(
             )
 
         # Write blobs
-        zipf.mkdir("blobs")
+        zipf.writestr("blobs/", "")
         for hash in hashes:
             zipf.writestr(
                 f"blobs/{hash}",