diff --git a/apps/user_ldap/group_ldap.php b/apps/user_ldap/group_ldap.php
index b29ebe30c5..aac3ed7891 100644
--- a/apps/user_ldap/group_ldap.php
+++ b/apps/user_ldap/group_ldap.php
@@ -232,7 +232,26 @@ class GROUP_LDAP extends lib\Access implements \OCP\GroupInterface {
 	 * @return bool
 	 */
 	public function groupExists($gid){
-		return in_array($gid, $this->getGroups());
+		if($this->connection->isCached('groupExists'.$gid)) {
+			return $this->connection->getFromCache('groupExists'.$gid);
+		}
+
+		//getting dn, if false the group does not exist. If dn, it may be mapped only, requires more checking.
+		$dn = $this->username2dn($gid);
+		if(!$dn) {
+			$this->connection->writeToCache('groupExists'.$gid, false);
+			return false;
+		}
+
+		//if group really still exists, we will be able to read its objectclass
+		$objcs = $this->readAttribute($dn, 'objectclass');
+		if(!$objcs || empty($objcs)) {
+			$this->connection->writeToCache('groupExists'.$gid, false);
+			return false;
+		}
+
+		$this->connection->writeToCache('groupExists'.$gid, true);
+		return true;
 	}
 
 	/**
diff --git a/apps/user_ldap/lib/access.php b/apps/user_ldap/lib/access.php
index 9abbd91c17..089548a69b 100644
--- a/apps/user_ldap/lib/access.php
+++ b/apps/user_ldap/lib/access.php
@@ -137,20 +137,6 @@ abstract class Access {
 		$dn = $this->ocname2dn($name, true);
 		if($dn) {
 			return $dn;
-		} else {
-			//fallback: user is not mapped
-			$filter = $this->combineFilterWithAnd(array(
-				$this->connection->ldapUserFilter,
-				$this->connection->ldapUserDisplayName . '=' . $name,
-			));
-			$result = $this->searchUsers($filter, 'dn');
-			if(isset($result[0]['dn'])) {
-				//try mapping, if names equalize return DN
-				$uid = $this->dn2username($result[0]['dn']);
-				if($uid == $name) {
-					return $result[0]['dn'];
-				}
-			}
 		}
 
 		return false;