diff --git a/mdgo/util/packmol.py b/mdgo/util/packmol.py
index c69e6bc2..97d79d37 100644
--- a/mdgo/util/packmol.py
+++ b/mdgo/util/packmol.py
@@ -19,7 +19,7 @@
 from typing import Dict, List, Optional, Union
 
 from pymatgen.core import Molecule
-from monty.os.path import which
+from shutil import which
 
 # from pymatgen.io.core import InputFile, InputSet, InputGenerator