If you’re connected to two or more displays, you can mirror your main display on the second display. Owning a MacBook, you will see your F7 key being embedded with icon showing two stacking blocks, that’s the shortcut to activate mirror display.
Apart of that, you can also slowly set your Mac to mirror display via Display Preference Panes:
- Open Apple ▸ System Preferences..
- Select Displays with its big blue screen icon
- Go under Arrangement section
- Check the Mirror Displays checkbox
If you’ve more than two displays, enabling this feature will make all your displays showing the same image as your main display. Let’s say it’s not what you want; You want to mirror your main display only on your 2nd display and left the 3rd display intact. It’s quite simple:
- Still on Display Preferences Pane under Arrangement
- Option Grab a display and drop it to another display, let’s say it’s your 2nd display. And you will get your 2nd display as the mirror displays while other displays are still in the form of extended displays