diff --git a/phpBB/phpbb/install/controller/install.php b/phpBB/phpbb/install/controller/install.php
index baa4e4807a..8bf9062b08 100644
--- a/phpBB/phpbb/install/controller/install.php
+++ b/phpBB/phpbb/install/controller/install.php
@@ -105,7 +105,7 @@ class install
 	{
 		if ($this->install_helper->is_phpbb_installed())
 		{
-			throw new http_exception(404, 'INSTALL_PHPBB_INSTALLED');
+			throw new http_exception(403, 'INSTALL_PHPBB_INSTALLED');
 		}
 
 		$this->template->assign_vars(array(
diff --git a/phpBB/phpbb/install/controller/update.php b/phpBB/phpbb/install/controller/update.php
index 8ecd8b3cb8..9fff11cae8 100644
--- a/phpBB/phpbb/install/controller/update.php
+++ b/phpBB/phpbb/install/controller/update.php
@@ -103,7 +103,7 @@ class update
 	{
 		if (!$this->install_helper->is_phpbb_installed())
 		{
-			throw new http_exception(404, 'INSTALL_PHPBB_NOT_INSTALLED');
+			throw new http_exception(403, 'INSTALL_PHPBB_NOT_INSTALLED');
 		}
 
 		$this->template->assign_vars(array(