diff --git a/phpBB/phpbb/storage/adapter/adapter_interface.php b/phpBB/phpbb/storage/adapter/adapter_interface.php
index 3208b5efc8..66de8c7dc7 100644
--- a/phpBB/phpbb/storage/adapter/adapter_interface.php
+++ b/phpBB/phpbb/storage/adapter/adapter_interface.php
@@ -99,9 +99,7 @@ interface adapter_interface
 	/*
 	 * Get space available in bytes.
 	 *
-	 * @throws \phpbb\storage\exception\exception		When unable to retrieve available storage space
-	 *
-	 * @return int	Returns available space
+	 * @return mixed	Returns available space or null when unable to retrieve available space
 	 */
 	public function free_space();
 }
diff --git a/phpBB/phpbb/storage/adapter/local.php b/phpBB/phpbb/storage/adapter/local.php
index b23d251ee7..3cde5a4fbb 100644
--- a/phpBB/phpbb/storage/adapter/local.php
+++ b/phpBB/phpbb/storage/adapter/local.php
@@ -432,11 +432,6 @@ class local implements adapter_interface, stream_interface
 	{
 		$free_space = @disk_free_space($this->root_path);
 
-		if ($free_space === false)
-		{
-			throw new exception('STORAGE_CANNOT_GET_FREE_SPACE');
-		}
-
-		return (int) $free_space;
+		return $free_space;
 	}
 }
diff --git a/phpBB/phpbb/storage/storage.php b/phpBB/phpbb/storage/storage.php
index 652b144907..f79b5bc32a 100644
--- a/phpBB/phpbb/storage/storage.php
+++ b/phpBB/phpbb/storage/storage.php
@@ -43,7 +43,7 @@ class storage
 	protected $factory;
 
 	/**
-	 * @var string
+	 * @var stringshould be caste
 	 */
 	protected $storage_name;
 
@@ -384,7 +384,7 @@ class storage
 			$this->db->sql_freeresult($result);
 		}
 
-		return $number_files;
+		return (int) $number_files;
 	}
 
 	/**
@@ -392,7 +392,7 @@ class storage
 	 *
 	 * @throws \phpbb\storage\exception\exception		When can't get available space
 	 *
-	 * @return int	Returns available space
+	 * @return mixed	Returns available space or null when unable to retrieve available space
 	 */
 	public function free_space()
 	{