diff --git a/letsencrypt/plugins/standalone/authenticator.py b/letsencrypt/plugins/standalone/authenticator.py
index 2ed60a096..971f90266 100644
--- a/letsencrypt/plugins/standalone/authenticator.py
+++ b/letsencrypt/plugins/standalone/authenticator.py
@@ -265,6 +265,7 @@ class StandaloneAuthenticator(common.Plugin):
         signal.signal(signal.SIGUSR1, self.client_signal_handler)
         signal.signal(signal.SIGUSR2, self.client_signal_handler)
 
+        sys.stdout.flush()
         fork_result = os.fork()
         Crypto.Random.atfork()
         if fork_result: