diff --git a/modules/admin/controllers/maintenance/CacheReset.php b/modules/admin/controllers/maintenance/CacheReset.php
index b40845f27..7eb18ad2c 100644
--- a/modules/admin/controllers/maintenance/CacheReset.php
+++ b/modules/admin/controllers/maintenance/CacheReset.php
@@ -95,7 +95,7 @@ class CacheReset extends Base
 					// If possible, use system command to speed up recursive deletion
 					if (function_exists('exec') && !preg_match('/(?<!_)exec/', ini_get('disable_functions')))
 					{
-						if (strncasecmp(\PHP_OS, 'win', 3) == 0)
+						if (\RX_WINDOWS)
 						{
 							@exec('rmdir /S /Q ' . escapeshellarg($tmp_dir));
 						}
diff --git a/modules/admin/controllers/maintenance/Cleanup.php b/modules/admin/controllers/maintenance/Cleanup.php
index e1870720b..5213679c0 100644
--- a/modules/admin/controllers/maintenance/Cleanup.php
+++ b/modules/admin/controllers/maintenance/Cleanup.php
@@ -176,7 +176,7 @@ class Cleanup extends Base
 		{
 			return $cache = true;
 		}
-		if (preg_match('/Win/i', \PHP_OS))
+		if (\RX_WINDOWS)
 		{
 			return $cache = false;
 		}