diff --git a/phpBB/includes/functions.php b/phpBB/includes/functions.php
index bbeaca9d1d..65bf1f9c65 100644
--- a/phpBB/includes/functions.php
+++ b/phpBB/includes/functions.php
@@ -703,7 +703,7 @@ if (!function_exists('stripos'))
 */
 function is_absolute($path)
 {
-	return ($path[0] == '/' || (DIRECTORY_SEPARATOR == '\\' && preg_match('#^[a-z]:/#i', $path))) ? true : false;
+	return ($path[0] == '/' || (DIRECTORY_SEPARATOR == '\\' && preg_match('#^[a-z]:[/\\\]#i', $path))) ? true : false;
 }
 
 /**