diff --git a/ak/ak_build.py b/ak/ak_build.py
index 5026a68..7434b8b 100644
--- a/ak/ak_build.py
+++ b/ak/ak_build.py
@@ -145,7 +145,7 @@ def _generate_repo_yaml(self, config, frozen):
         config = yaml.safe_load(open(config).read())
         frozen_data = {}
         if local.path(frozen).is_file():
-            frozen_data = yaml.safe_load(open(frozen).read())
+            frozen_data = yaml.safe_load(open(frozen).read()) or {}
 
         for key in config:
             if config[key].get("prebuild"):