diff --git a/scripts/config.py b/scripts/config.py
index 3b2aa63a7..1a2b1595e 100755
--- a/scripts/config.py
+++ b/scripts/config.py
@@ -384,7 +384,7 @@ if __name__ == '__main__':
                     sys.stdout.write(value + '\n')
             return args.symbol not in config
         elif args.command == 'set':
-            if not args.force and args.symbol not in config:
+            if not args.force and args.symbol not in config.settings:
                 sys.stderr.write("A #define for the symbol {} "
                                  "was not found in {}"
                                  .format(args.symbol, args.file))