diff --git a/src/calibre/gui2/dbus_export/menu.py b/src/calibre/gui2/dbus_export/menu.py
index 6b682625a2..38c013b7de 100644
--- a/src/calibre/gui2/dbus_export/menu.py
+++ b/src/calibre/gui2/dbus_export/menu.py
@@ -237,7 +237,7 @@ class DBusMenu(QObject):
         return parent_id, props, self.get_layout_children(parent_id, depth, property_names)
 
     def get_layout_children(self, parent_id, depth, property_names):
-        ans = dbus.Array(signature='(ia{sv}av)')
+        ans = dbus.Array(signature='v')
         ac = self.id_to_action(parent_id)
         if ac is not None and depth != 0 and ac.menu() is not None:
             for child in menu_actions(ac.menu()):
diff --git a/src/calibre/gui2/dbus_export/tray.py b/src/calibre/gui2/dbus_export/tray.py
index 85e02a0a85..07483de1e6 100644
--- a/src/calibre/gui2/dbus_export/tray.py
+++ b/src/calibre/gui2/dbus_export/tray.py
@@ -192,7 +192,7 @@ class StatusNotifierItemAPI(Object):
     def Menu(self):
         return dbus.ObjectPath(self.dbus_menu.object_path)
 
-    @dbus_property(IFACE, signature='i')
+    @dbus_property(IFACE, signature='u')
     def WindowId(self):
         return 0