diff --git a/phpBB/includes/cache/driver/file.php b/phpBB/includes/cache/driver/file.php
index 699402af84..b20c0064ea 100644
--- a/phpBB/includes/cache/driver/file.php
+++ b/phpBB/includes/cache/driver/file.php
@@ -214,7 +214,7 @@ class phpbb_cache_driver_file extends phpbb_cache_driver_base
 
 		while (($entry = readdir($dir)) !== false)
 		{
-			if (strpos($entry, 'container') === false &&
+			if (strpos($entry, 'container') !== 0 &&
 				strpos($entry, 'sql_') !== 0 &&
 				strpos($entry, 'data_') !== 0 &&
 				strpos($entry, 'ctpl_') !== 0 &&
diff --git a/phpBB/includes/cache/driver/memory.php b/phpBB/includes/cache/driver/memory.php
index 8b4ecb6cbf..98ac02b161 100644
--- a/phpBB/includes/cache/driver/memory.php
+++ b/phpBB/includes/cache/driver/memory.php
@@ -162,7 +162,7 @@ abstract class phpbb_cache_driver_memory extends phpbb_cache_driver_base
 
 		while (($entry = readdir($dir)) !== false)
 		{
-			if (strpos($entry, 'container') === false &&
+			if (strpos($entry, 'container') !== 0 &&
 				strpos($entry, 'sql_') !== 0 &&
 				strpos($entry, 'data_') !== 0 &&
 				strpos($entry, 'ctpl_') !== 0 &&