According to Apple's website, you will receive notifications from the Mac App Store (via Notification Center) when updates are available. Yet I see no section for Mac App Store in Notifications Pref pane, and do not receive notifications when updates are available. Does anyone have any explanation for this? See "Notification Center" section here: https://developer.apple.com/technologies/mountain-lion/ EDIT: Maybe it's only after the updates have been downloaded and are ready to install? See system update pref pane.