diff --git a/workflow/engine/src/ProcessMaker/BusinessModel/ProcessPermissions.php b/workflow/engine/src/ProcessMaker/BusinessModel/ProcessPermissions.php
index ca5a754c1..862907bd8 100644
--- a/workflow/engine/src/ProcessMaker/BusinessModel/ProcessPermissions.php
+++ b/workflow/engine/src/ProcessMaker/BusinessModel/ProcessPermissions.php
@@ -5,6 +5,7 @@ use Behat\Behat\Exception\Exception;
 use \G;
 use \Criteria;
 use \ObjectPermissionPeer;
+use \Exception as StandardException;
 
 /**
  * @author Brayan Pereyra (Cochalo) <brayan@colosa.com>
@@ -224,8 +225,8 @@ class ProcessPermissions
             if ($opUid != '') {
                 $opUid  = $this->validateOpUid($opUid);
             }
-            if (empty($data['USR_UID']) || $data['USR_UID'] === "null") {
-                throw (new \Exception(\G::LoadTranslation("ID_SELECT_USER_OR_GROUP")));
+            if (empty($data['USR_UID']) || (isset($data['USR_UID']) && $data['USR_UID'] === "null")) {
+                throw (new StandardException(G::LoadTranslation("ID_SELECT_USER_OR_GROUP")));
             }
             if ($data['OP_USER_RELATION'] == "1") {
                 $this->validateUsrUid($data['USR_UID']);