diff --git a/qubesmanager/settings.py b/qubesmanager/settings.py
index 9be8256..b25403d 100755
--- a/qubesmanager/settings.py
+++ b/qubesmanager/settings.py
@@ -966,6 +966,8 @@ class VMSettingsWindow(ui_settingsdlg.Ui_SettingsDialog, QtGui.QDialog):
 
         self.update_pvh_dont_support_devs()
 
+        self.dev_list.setEnabled(not self.vm.is_running())
+
     def __apply_devices_tab__(self):
         msg = []