diff --git a/phpgwapi/inc/class.accounts_ldap.inc.php b/phpgwapi/inc/class.accounts_ldap.inc.php
index 42896a65df..f96bc5b0eb 100644
--- a/phpgwapi/inc/class.accounts_ldap.inc.php
+++ b/phpgwapi/inc/class.accounts_ldap.inc.php
@@ -322,7 +322,7 @@ class accounts_ldap
 			$data['account_type'] = 'u';
 
 			// Check if an account already exists as system user, and if it does deny creation
-			if (!$GLOBALS['egw_info']['server']['ldap_allow_systemusernames'] &&
+			if (!$GLOBALS['egw_info']['server']['ldap_allow_systemusernames'] && !$old &&
 				function_exists('posix_getpwnam') && posix_getpwnam($data['account_lid']))
 			{
 				throw new egw_exception_wrong_userinput(lang('There already is a system-user with this name. User\'s should not have the same name as a systemuser'));