diff --git a/apps/user_ldap/lib/Access.php b/apps/user_ldap/lib/Access.php
index 45ab3c42399..1cc0c62ff1d 100644
--- a/apps/user_ldap/lib/Access.php
+++ b/apps/user_ldap/lib/Access.php
@@ -1369,8 +1369,11 @@ class Access extends LDAPUtility {
 		// Remove unknown leftover entities
 		$name = preg_replace('#&[^;]+;#', '', $name);
 
+		// Replacements
+		$name = str_replace(' ', '_', $name);
+
 		// Every remaining disallowed characters will be removed
-		$name = preg_replace('/[^a-zA-Z0-9 _.@-]/u', '', $name);
+		$name = preg_replace('/[^a-zA-Z0-9_.@-]/u', '', $name);
 
 		if (strlen($name) > 64) {
 			$name = hash('sha256', $name, false);