i an wary of my iMac doing auto updates when i am not near it. my problem is that some system updates while they seem ok may have incompatible problems with other apps. eg. my system did and update, and not my Silverfast scanner driver does not work under the latest system, and need to update to a new version, which with foreign exchange rates comes to over $900 Australian...
so i always shut my mac down when i am not near it.
Regards, Sandy