diff --git a/wp-admin/upgrade-schema.php b/wp-admin/upgrade-schema.php
index e02dc9be0f..b8bc3e0caf 100644
--- a/wp-admin/upgrade-schema.php
+++ b/wp-admin/upgrade-schema.php
@@ -134,7 +134,7 @@ CREATE TABLE $wpdb->users (
   user_status int(11) NOT NULL default '0',
   display_name varchar(250) NOT NULL default '',
   PRIMARY KEY  (ID),
-  UNIQUE KEY user_login (user_login)
+  KEY user_login (user_login)
 );
 CREATE TABLE $wpdb->usermeta (
   umeta_id bigint(20) NOT NULL auto_increment,