Apple decided to make macOS sierra an “Automatic Update” today. Until now it was just listed in the App Store. People had to click on it to update. If you are running a machine with an older OS that will run Sierra and do not wish to update then read on friends.
Take a look at the below image of the App Store Pref Pane. I have mine set to download and update apps automatically.
However, I have the “Install macOS Updates” turned off. I do not wish to get an update to my operating system until I am good and ready. If you really don’t want to bother with Sierra now I suggest you turn off both “newly available updates” AND “install macOS updates”. That is the way to be safe.
Buy the way, if the Sierra update has downloaded already you can just cancel the install and/or delete it from your Applications Folder. I am enjoying Sierra, but if you are not ready for it, you don’t have to install it. So there!