Keeping your software up to date is one of the most important things you can do to maintain the security of your Mac. That includes installing all available macOS software updates, including security updates and the background updates described in this article.

Background updates include security-configuration updates and system data files, which are automatically installed by default. They don't cause your Mac to restart, but some take effect only after you restart.

Background updates include:

Security-configuration updates, which help make your Mac more secure by identifying malicious software and preventing its installation. When you restart your Mac, these updates also remove any malicious software that is identified but already installed.

System data files, which provide new word lists, speech-recognition assets, voice assets, better suggestions for contacts and events, and more. Some system data files are installed only when you turn on or use features that require them.

To make sure that you always get these background updates promptly, keep the “Install system data files and security updates” setting enabled in Software Update preferences. Go to System Preferences > Software Update, then click Advanced.