diff --git a/configuration.org b/configuration.org
index 9b1cd94..bfa25aa 100644
--- a/configuration.org
+++ b/configuration.org
@@ -105,8 +105,8 @@ Taken from [[http://ergoemacs.org/emacs/emacs_set_backup_into_a_directory.html][
 #+BEGIN_SRC emacs-lisp
 (defun xah/backup-file-name (fpath)
     "Return a new file path for FPATH under `user-emacs-cache-directory'"
-    (let* ((backup-root-dir (concat user-emacs-cache-directory "/backup"))
-           (file-path (replace-regexp-in-string "[A-Za-z]:" ""))
+    (let* ((backup-root-dir (expand-file-name "backup" user-emacs-cache-directory))
+           (file-path (replace-regexp-in-string "[A-Za-z]:" "" fpath))
            (backup-file-path (replace-regexp-in-string "//" "/" (concat backup-root-dir file-path "~"))))
       (make-directory (file-name-directory backup-file-path) (file-name-directory backup-file-path))
       backup-file-path))