diff --git a/image_creator/os_type/unix.py b/image_creator/os_type/unix.py
index 06eccbf88f293878f82d7a688294cb76c6cad69b..e23f3513844f721a1590eb397efda374069a241d 100644
--- a/image_creator/os_type/unix.py
+++ b/image_creator/os_type/unix.py
@@ -63,7 +63,7 @@ class Unix(OSBase):
 
             user, passwd = match.groups()
             if len(passwd) > 0 and passwd[0] == '!':
-                warn("Ignoring locked %s account." % user)
+                self.out.warn("Ignoring locked %s account." % user)
             else:
                 users.append(user)