diff --git a/fxconv/fxconv-main.py b/fxconv/fxconv-main.py
index c1d18a4..6954936 100755
--- a/fxconv/fxconv-main.py
+++ b/fxconv/fxconv-main.py
@@ -114,6 +114,9 @@ def main():
 		metadata = fxconv.Metadata(path=metadata_file)
 		params = metadata.rules_for(input)
 
+		if params is None:
+			return err(f"no metadata specified for {input}")
+
 		if "section" in params:
 			target["section"] = params["section"]