diff --git a/modoboa_installer/scripts/postfix.py b/modoboa_installer/scripts/postfix.py
index c9d964f2..42f96a56 100644
--- a/modoboa_installer/scripts/postfix.py
+++ b/modoboa_installer/scripts/postfix.py
@@ -77,7 +77,7 @@ def post_run(self):
         chroot_dir = "/var/spool/postfix/etc"
         chroot_files = ["services", "resolv.conf"]
         if not os.path.exists(chroot_dir):
-            os.mkdir(chroot_dir)
+            utils.mkdir(chroot_dir)
         for f in chroot_files:
             path = os.path.join(chroot_dir, f)
             if not os.path.exists(path):
diff --git a/modoboa_installer/utils.py b/modoboa_installer/utils.py
index 0550f5e1..ac2548e9 100644
--- a/modoboa_installer/utils.py
+++ b/modoboa_installer/utils.py
@@ -76,7 +76,7 @@ def dist_name():
 def mkdir(path, mode, uid, gid):
     """Create a directory."""
     if not os.path.exists(path):
-        os.mkdir(path, mode)
+        os.makedirs(path, mode)
     else:
         os.chmod(path, mode)
     os.chown(path, uid, gid)