diff --git a/lib/classes/module/console/taskrun.class.php b/lib/classes/module/console/taskrun.class.php
index f52ee7621e..e00298a2fc 100644
--- a/lib/classes/module/console/taskrun.class.php
+++ b/lib/classes/module/console/taskrun.class.php
@@ -143,7 +143,7 @@ class module_console_taskrun extends Command
 
         if (time() - $start > 0) {
             if ($this->shedulerPID) {
-                if ( ! posix_kill($this->shedulerPID, 0)) {
+                if (function_exists('posix_kill') && !posix_kill($this->shedulerPID, 0)) {
                     if (method_exists($this->task, 'signal')) {
                         $this->task->signal('SIGNAL_SCHEDULER_DIED');
                     } else {
diff --git a/lib/classes/task/Scheduler.class.php b/lib/classes/task/Scheduler.class.php
index 8df09ae8be..e3da9688b2 100755
--- a/lib/classes/task/Scheduler.class.php
+++ b/lib/classes/task/Scheduler.class.php
@@ -54,6 +54,11 @@ class task_Scheduler
      */
     public function run()
     {
+        if (function_exists('pcntl_signal')) {
+            // avoid <defunct> php when a task ends
+            pcntl_signal(SIGCHLD, SIG_IGN);
+        }
+
         $appbox = appbox::get_instance(\bootstrap::getCore());
         $registry = $appbox->get_registry();
 
diff --git a/lib/classes/task/abstract.class.php b/lib/classes/task/abstract.class.php
index 5608a0be68..5017a566e0 100755
--- a/lib/classes/task/abstract.class.php
+++ b/lib/classes/task/abstract.class.php
@@ -334,7 +334,7 @@ abstract class task_abstract
 
     abstract public function help();
 
-    public function __construct($taskid, Logger $logger)
+    public function __construct($taskid, Logger $logger = NULL)
     {
         $this->logger = $logger;
 
diff --git a/lib/classes/task/manager.class.php b/lib/classes/task/manager.class.php
index 34518472b1..454ed7f92e 100755
--- a/lib/classes/task/manager.class.php
+++ b/lib/classes/task/manager.class.php
@@ -73,9 +73,9 @@ class task_manager
 
         $core = \bootstrap::getCore();
 
-        if ( ! $logger) {
-            $logger = $core['monolog'];
-        }
+//        if ( ! $logger) {
+//            $logger = $core['monolog'];
+//        }
 
         $sql = "SELECT task2.* FROM task2 ORDER BY task_id ASC";
         $stmt = $this->appbox->get_connection()->prepare($sql);
@@ -113,9 +113,9 @@ class task_manager
     {
         $core = \bootstrap::getCore();
 
-        if ( ! $logger) {
-            $logger = $core['monolog'];
-        }
+//        if ( ! $logger) {
+//            $logger = $core['monolog'];
+//        }
 
         $tasks = $this->getTasks(false, $logger);