diff --git a/fifloader.py b/fifloader.py
index 598bb311..17a8feab 100755
--- a/fifloader.py
+++ b/fifloader.py
@@ -340,7 +340,7 @@ def run(args):
         if args.update:
             loadargs.append('--update')
         loadargs.append('-')
-        subprocess.run(loadargs, input=json.dumps(out), text=True)
+        subprocess.run(loadargs, input=json.dumps(out), text=True, check=True)
 
 def main():
     """Main loop."""