Unfortunately, bad updates from antivirus vendors killing computers happens from time to time.  We've never had it happen to our clients, but that's possibly luck as it has happened to some big name security companies.  While it's early in the incident, if I'm reading correctly many machines will recover but some will need manual intervention to get them up and running.

If any of our fellow IT support companies have a number of machines in or near Auckland that need manual intervention to get up and running and you'd like some extra hands, DM me and I'll rouse our troops.