diff --git a/artiq/frontend/artiq_client.py b/artiq/frontend/artiq_client.py
index 7f5c63d7c..3210aa704 100755
--- a/artiq/frontend/artiq_client.py
+++ b/artiq/frontend/artiq_client.py
@@ -175,7 +175,7 @@ def _action_scan_devices(remote, args):
 
 
 def _action_scan_repository(remote, args):
-    if args.async:
+    if getattr(args, "async"):
         remote.scan_repository_async(args.revision)
     else:
         remote.scan_repository(args.revision)