diff --git a/workflow/engine/classes/class.derivation.php b/workflow/engine/classes/class.derivation.php
index 6ad37ca7a..087fd15e1 100755
--- a/workflow/engine/classes/class.derivation.php
+++ b/workflow/engine/classes/class.derivation.php
@@ -605,6 +605,9 @@ class Derivation
                 break;
             case "MULTIPLE_INSTANCE":
                 $userFields = $this->getUsersFullNameFromArray($this->getAllUsersFromAnyTask($nextAssignedTask["TAS_UID"]));
+                if(empty($userFields)){
+                    throw (new Exception( G::LoadTranslation( 'ID_NO_USERS' ) ));
+                }
                 break;
             case "MULTIPLE_INSTANCE_VALUE_BASED":
                 $arrayApplicationData = $this->case->loadCase($tasInfo["APP_UID"]);
@@ -690,7 +693,7 @@ class Derivation
                 "elementOrigin" => ["uid" => $elementOriginUid, "type" => "bpmnActivity"],
                 "elementDest"   => ["uid" => $elementDestUid,   "type" => "bpmnActivity"]
             ];
- 
+
             foreach ($arrayElement as $key => $value) {
                 $arrayElementTaskRelationData = $elementTaskRelation->getElementTaskRelationWhere(
                     [