diff --git a/src/wp-admin/includes/class-wp-filesystem-base.php b/src/wp-admin/includes/class-wp-filesystem-base.php
index 8080aef1a7..1ea44eb786 100644
--- a/src/wp-admin/includes/class-wp-filesystem-base.php
+++ b/src/wp-admin/includes/class-wp-filesystem-base.php
@@ -95,7 +95,7 @@ class WP_Filesystem_Base {
 	public function abspath() {
 		$folder = $this->find_folder(ABSPATH);
 		// Perhaps the FTP folder is rooted at the WordPress install, Check for wp-includes folder in root, Could have some false positives, but rare.
-		if ( ! $folder && $this->is_dir('/wp-includes') )
+		if ( ! $folder && $this->is_dir( '/' . WPINC ) )
 			$folder = '/';
 		return $folder;
 	}