diff --git a/phpBB/install/schemas/mssql_schema.sql b/phpBB/install/schemas/mssql_schema.sql
index 6de6a63ad7..06649eefbc 100644
--- a/phpBB/install/schemas/mssql_schema.sql
+++ b/phpBB/install/schemas/mssql_schema.sql
@@ -679,7 +679,7 @@ GO
  CREATE  INDEX [IX_phpbb_sessions_keys] ON [phpbb_sessions_keys]([key_id], [user_id]) ON [PRIMARY]
 GO
 
- CREATE  INDEX [IX_phpbb_sessions_keys] ON [phpbb_sessions_keys]([last_login]) ON [PRIMARY]
+ CREATE  INDEX [IX_phpbb_sessions_keys_1] ON [phpbb_sessions_keys]([last_login]) ON [PRIMARY]
 GO
 
  CREATE  INDEX [IX_phpbb_topics] ON [phpbb_topics]([forum_id], [topic_type], [topic_first_post_id], [topic_last_post_id]) ON [PRIMARY]
diff --git a/phpBB/install/update_to_latest.php b/phpBB/install/update_to_latest.php
index bb8170271c..b766ee58ae 100644
--- a/phpBB/install/update_to_latest.php
+++ b/phpBB/install/update_to_latest.php
@@ -570,7 +570,7 @@ switch ($row['config_value'])
 				$sql[] = 'CREATE TABLE [' . $table_prefix . 'sessions_keys] ([key_id] [char] (32) NOT NULL , [user_id] [int] NOT NULL , [last_ip] [char] (8) NOT NULL , [last_login] [int] NOT NULL) ON [PRIMARY]';
 
 				$sql[] = 'CREATE INDEX [IX_' . $table_prefix . 'sessions_keys] ON [' . $table_prefix . 'sessions_keys]([key_id], [user_id]) ON [PRIMARY]';
-				$sql[] = 'CREATE  INDEX [IX_' . $table_prefix . 'sessions_keys] ON [' . $table_prefix . 'sessions_keys]([last_login]) ON [PRIMARY]';
+				$sql[] = 'CREATE  INDEX [IX_' . $table_prefix . 'sessions_keys_1] ON [' . $table_prefix . 'sessions_keys]([last_login]) ON [PRIMARY]';
 				break;
 
 			case 'msaccess':