diff --git a/lib/classes/event/message_sent.php b/lib/classes/event/message_sent.php
index 2ddb1b20d0e..91a759e8860 100644
--- a/lib/classes/event/message_sent.php
+++ b/lib/classes/event/message_sent.php
@@ -65,8 +65,13 @@ class message_sent extends base {
      * @return string
      */
     public function get_description() {
-        return 'The user with the id \'' . $this->userid . '\' sent a message to the user with the id  \'' .
-            $this->relateduserid . '\'.';
+        // Check that we are sending from a valid user.
+        if ($this->userid > 0) {
+            return 'The user with the id \'' . $this->userid . '\' sent a message to the user with the id \'' .
+                $this->relateduserid . '\'.';
+        } else {
+            return 'A message was sent by the system to the user with the id \'' . $this->relateduserid . '\'.';
+        }
     }
 
     /**
@@ -75,8 +80,14 @@ class message_sent extends base {
      * @return array
      */
     protected function get_legacy_logdata() {
-        return array(SITEID, 'message', 'write', 'index.php?user=' . $this->userid . '&id=' . $this->relateduserid .
-            '&history=1#m' . $this->other['messageid'], $this->userid);
+        // The add_to_log function was only ever called when we sent a message from one user to another. We do not want
+        // to return the legacy log data if we are sending a system message, so check that the userid is valid.
+        if ($this->userid > 0) {
+            return array(SITEID, 'message', 'write', 'index.php?user=' . $this->userid . '&id=' . $this->relateduserid .
+                '&history=1#m' . $this->other['messageid'], $this->userid);
+        }
+
+        return null;
     }
 
     /**
diff --git a/lib/messagelib.php b/lib/messagelib.php
index 0b4346f55e4..9d99f25f6b3 100644
--- a/lib/messagelib.php
+++ b/lib/messagelib.php
@@ -247,10 +247,21 @@ function message_send($eventdata) {
         }
     }
 
+    // We may be sending a message from the 'noreply' address, which means we are not actually sending a
+    // message from a valid user. In this case, we will set the userid to 0 and the context to system.
+    // Check if the userid is valid.
+    if ($eventdata->userfrom->id > 0) {
+        $userfromid = $eventdata->userfrom->id;
+        $context = context_user::instance($eventdata->userfrom->id);
+    } else {
+        $userfromid = 0;
+        $context = context_system::instance();
+    }
+
     // Trigger event for sending a message.
     $event = \core\event\message_sent::create(array(
-        'userid' => $eventdata->userfrom->id,
-        'context'  => context_user::instance($eventdata->userfrom->id),
+        'userid' => $userfromid,
+        'context'  => $context,
         'relateduserid' => $eventdata->userto->id,
         'other' => array(
             'messageid' => $messageid // Can't use this as the objectid as it can either be the id in the 'message_read'