--- a/src/pyams_scheduler/include.py	Fri Nov 09 11:54:43 2018 +0100
+++ b/src/pyams_scheduler/include.py	Fri Nov 09 12:00:30 2018 +0100
@@ -70,47 +70,49 @@
         # check if port is available
         handler_address = settings.get(SCHEDULER_HANDLER_KEY, '127.0.0.1:5555')
         hostname, port = handler_address.split(':')
-        if not is_port_in_use(int(port), hostname):
-            # get database connection
-            connection = get_connection_from_settings(settings)
-            root = connection.root()
-            # get application
-            application_name = settings.get(PYAMS_APPLICATION_SETTINGS_KEY, PYAMS_APPLICATION_DEFAULT_NAME)
-            application = root.get(application_name)
-            if application is not None:
-                sm = application.getSiteManager()
-                set_local_registry(sm)
-                process = None
+        if is_port_in_use(int(port), hostname):
+            logger.info("Scheduler port already used, aborting...")
+            return
+        # get database connection
+        connection = get_connection_from_settings(settings)
+        root = connection.root()
+        # get application
+        application_name = settings.get(PYAMS_APPLICATION_SETTINGS_KEY, PYAMS_APPLICATION_DEFAULT_NAME)
+        application = root.get(application_name)
+        if application is not None:
+            sm = application.getSiteManager()
+            set_local_registry(sm)
+            process = None
+            try:
+                scheduler_util = sm.get(SCHEDULER_NAME)
                 try:
-                    scheduler_util = sm.get(SCHEDULER_NAME)
-                    try:
-                        zodb_name = scheduler_util.zodb_name
-                    except ComponentLookupError:
-                        pass
-                    else:
-                        # create scheduler process
-                        process = SchedulerProcess(handler_address,
-                                                   SchedulerMessageHandler,
-                                                   settings.get(SCHEDULER_AUTH_KEY),
-                                                   settings.get(SCHEDULER_CLIENTS_KEY),
-                                                   registry)
-                        # load tasks
-                        for task in scheduler_util.values():
-                            trigger = task.get_trigger(registry)
-                            logger.debug("Adding scheduler job for task '{0.name}'".format(task))
-                            process.scheduler.add_job(task, trigger,
-                                                      id=str(task.internal_id),
-                                                      name=task.name,
-                                                      kwargs={'zodb_name': zodb_name,
-                                                              'registry': registry})
-                        # start process
-                        logger.info("Starting tasks scheduler {0!r}...".format(process))
-                        process.start()
-                        if process.is_alive():
-                            atexit.register(process_exit_func, process=process)
-                            logger.info("Started tasks scheduler with PID {0}.".format(process.pid))
-                finally:
-                    if process and not process.is_alive():
-                        process.terminate()
-                        process.join()
-                    set_local_registry(None)
+                    zodb_name = scheduler_util.zodb_name
+                except ComponentLookupError:
+                    pass
+                else:
+                    # create scheduler process
+                    process = SchedulerProcess(handler_address,
+                                               SchedulerMessageHandler,
+                                               settings.get(SCHEDULER_AUTH_KEY),
+                                               settings.get(SCHEDULER_CLIENTS_KEY),
+                                               registry)
+                    # load tasks
+                    for task in scheduler_util.values():
+                        trigger = task.get_trigger(registry)
+                        logger.debug("Adding scheduler job for task '{0.name}'".format(task))
+                        process.scheduler.add_job(task, trigger,
+                                                  id=str(task.internal_id),
+                                                  name=task.name,
+                                                  kwargs={'zodb_name': zodb_name,
+                                                          'registry': registry})
+                    # start process
+                    logger.info("Starting tasks scheduler {0!r}...".format(process))
+                    process.start()
+                    if process.is_alive():
+                        atexit.register(process_exit_func, process=process)
+                        logger.info("Started tasks scheduler with PID {0}.".format(process.pid))
+            finally:
+                if process and not process.is_alive():
+                    process.terminate()
+                    process.join()
+                set_local_registry(None)