By rights, preference settings in an app should only control the behaviour of that app. Settings for macOS behaviours should be controlled in System Preferences, after all that’s what the name says. However, over the years Apple has hidden some away in its bundled apps, leaving users confused as to how these settings get changed without their control. Here’s a list of useful and important system settings which you might struggle to find otherwise. For good measure, I’ve included some which, although placed logically, aren’t easy to remember.

Default email reader

This is set in the Mail app’s Preferences > General; third-party mail clients may also assist in checking this is set correctly.

Default calendar app

This is set in the Calendar app’s Preferences > General.

Default for calls (default call handler)

This is set in the FaceTime app’s Preferences > Settings. It may be changed without warning by third-party apps like Skype, but they don’t offer the control in their own preferences, which can cause confusion.

Default Script Editor

This is set in Script Editor’s Preferences > General.

Script menu

This too is set in Script Editor’s Preferences > General.

App Store Automatic Updates

Although correctly placed, remember that this is set in the App Store app’s Preferences, not in the Software Update pane with other update options.

Shared with You

New with Monterey, this covers content shared in Messages which appears in other apps, and control over whether that sharing is automatic. This is set in the Messages app’s Preferences > Shared with You for all such shared content.

iTunes authorisation

This is controlled in the Music and TV apps’ menu Account > Authorisations.

Default web browser

This is set in the General pane in System Preferences; third-party browsers may offer to change this setting for you.

Screenshot options

To change the destination and other details for screenshots, press Command-Shift-5 for its floating panel with the Options menu.

There are, of course, several third-party apps which give more coherent and extensive access to these and other controls. But it’s frustrating that instead of rationalising them, macOS only seems to proliferate them.

I’m grateful to Martina, who discovered that placing a FaceTime call from Messages would instead connect via Skype. It took me a long time to realise that was controlled in neither Messages nor Skype, but in FaceTime.