diff --git a/core/postfix/start.py b/core/postfix/start.py
index 509f961a..80c1c4bf 100755
--- a/core/postfix/start.py
+++ b/core/postfix/start.py
@@ -14,6 +14,8 @@ from socrate import system, conf
 
 log.basicConfig(stream=sys.stderr, level=os.environ.get("LOG_LEVEL", "WARNING"))
 
+os.system("flock -n /queue/pid/master.pid rm /queue/pid/master.pid")
+
 def start_podop():
     os.setuid(getpwnam('postfix').pw_uid)
     os.makedirs('/dev/shm/postfix',mode=0o700, exist_ok=True)
diff --git a/towncrier/newsfragments/1483.bugfix b/towncrier/newsfragments/1483.bugfix
new file mode 100644
index 00000000..16e28f39
--- /dev/null
+++ b/towncrier/newsfragments/1483.bugfix
@@ -0,0 +1 @@
+Remove postfix's master.pid on startup if there is no other instance running