diff --git a/SeedDMS_Core/Core/inc.ClassDocument.php b/SeedDMS_Core/Core/inc.ClassDocument.php
index d3ce04a30..27de15098 100644
--- a/SeedDMS_Core/Core/inc.ClassDocument.php
+++ b/SeedDMS_Core/Core/inc.ClassDocument.php
@@ -707,6 +707,12 @@ class SeedDMS_Core_Document extends SeedDMS_Core_Object { /* {{{ */
 	function setOwner($newOwner) { /* {{{ */
 		$db = $this->_dms->getDB();
 
+        if(!$newOwner)
+            return false;
+
+        if(!$newOwner->isType('user'))
+            return false;
+
 		$queryStr = "UPDATE `tblDocuments` set `owner` = " . $newOwner->getID() . " WHERE `id` = " . $this->_id;
 		if (!$db->getResult($queryStr))
 			return false;