Apple developed auto updates some time ago but this is the first time it’s taken advantage of the technique.
Microsoft has been auto updating its operating systems for quite some while, as security threats come to light.
The update patches problems highlighted by Carnegie Mellon University and the US Department of Homeland Security, relating to a part of Apple’s OSX operating system dubbed the network time protocol.
Apple is often perceived as having secure machines not subject to the type of threat Windows machines face.
Apple said the update doesn’t even need people to restart their machines, meaning that most people will have been unaware of the action taken.