diff --git a/lam/lib/modules/inetLocalMailRecipient.inc b/lam/lib/modules/inetLocalMailRecipient.inc
index d410b258..15429e9e 100644
--- a/lam/lib/modules/inetLocalMailRecipient.inc
+++ b/lam/lib/modules/inetLocalMailRecipient.inc
@@ -227,14 +227,9 @@ class inetLocalMailRecipient extends baseModule {
 			// check if address has correct format
 			if (get_preg($_POST['localAdr'], 'mailLocalAddress')) {
 				// check if new address is not already in database
-				$data = $_SESSION['cache']->get_cache('mailLocalAddress', 'inetLocalMailRecipient', 'user');
-				$keys = array_keys($data);
-				for ($i = 0; $i < sizeof($keys); $i++) {
-					$adrList = $data[$keys[$i]];
-					if (in_array_ignore_case($_POST['localAdr'], $adrList)) {
-						$errors[] = array('WARN', _('This mail address is already in use:') . " " . $_POST['localAdr'], $keys[$i]);
-						break;
-					}
+				$data = searchLDAPByAttribute('mailLocalAddress', $_POST['localAdr'], 'inetLocalMailRecipient', array('dn'), array('user'));
+				if (sizeof($data) > 0) {
+					$errors[] = array('WARN', _('This mail address is already in use:') . " " . $_POST['localAdr'], $data[0]['dn']);
 				}
 				$this->attributes['mailLocalAddress'][] = $_POST['localAdr'];
 			}
diff --git a/lam/lib/modules/inetOrgPerson.inc b/lam/lib/modules/inetOrgPerson.inc
index ff0b73c8..b90df674 100644
--- a/lam/lib/modules/inetOrgPerson.inc
+++ b/lam/lib/modules/inetOrgPerson.inc
@@ -940,9 +940,10 @@ class inetOrgPerson extends baseModule implements passwordService {
 		}
 		if (!$this->isBooleanConfigOptionSet('inetOrgPerson_hideManager')) {
 			// get list of existing users for manager attribute
-			$dnUsers = $_SESSION['cache']->get_cache('uid', 'inetOrgPerson', 'user');
-			if (!is_array($dnUsers)) $dnUsers = array();
-			$dnUsers = array_keys($dnUsers);
+			$dnUsers = searchLDAPByAttribute(null, null, 'inetOrgPerson', array('dn'), array('user'));
+			for ($i = 0; $i < sizeof($dnUsers); $i++) {
+				$dnUsers[$i] = $dnUsers[$i]['dn'];
+			}
 			usort($dnUsers, array($_SESSION['ldap'], 'cmp_array'));
 			array_unshift($dnUsers, '-');
 			$options = array();