diff --git a/gvafile/osusers/tasks.py b/gvafile/osusers/tasks.py
index 5035169..49b5a6c 100644
--- a/gvafile/osusers/tasks.py
+++ b/gvafile/osusers/tasks.py
@@ -60,7 +60,7 @@ def setup_file_sftp_userdir(username):
             stderr=subprocess.STDOUT)
     except subprocess.CalledProcessError as exc:
         _logger.exception(
-            'could not create SFTP directory for user {0}: {1}',
+            'could not create SFTP directory for user %s: %s',
             username, exc.output
         )
         raise Reject(exc, requeue=False)