Do not try to use dbus when showing notifications under windows

init.el

@@ -916,7 +916,8 @@ With given ARG, display files in `db/important-document-path’."
 (use-package org-clock
   :defer t
   :commands (org-clock-save)
-  :init (setq org-clock-history-length 23
+  :init (progn
+          (setq org-clock-history-length 23
                 org-clock-in-resume t
                 org-clock-into-drawer t
                 org-clock-idle-time nil
@@ -939,6 +940,12 @@ With given ARG, display files in `db/important-document-path’."
                 org-clock-persist t
                 org-clock-persist-query-resume nil
                 org-time-stamp-rounding-minutes '(1 1))
+
+          ;; On Windows, we don't have dbus to show notifications; default to
+          ;; `message' instead
+          (when on-windows
+            (setq org-show-notification-handler #'message)))
+
   :config (progn
             (org-clock-persistence-insinuate)