To quit (close) a Mac app normally, choose Quit from the app's menu in the menu bar, or press Command (⌘)-Q. If the app doesn't quit, follow these steps to force the app to quit.
How to force an app to quit
Jun 23, 2019 For those new to the Mac, just remember that some apps remain running even if their windows are closed. In this case, either select the app to make it active. Then press the keyboard shortcut Command-Q or right-click on the app’s icon and choose Quit from the menu that appears. Sep 25, 2018 In fact, even if you explicitly quit Messages.app the unread messages app icon remains and new message notifications come display. I don't think this is a bug - it feels like a effort for the macOS Messages app to match the behaviour to the iOS counterpart. E.g., on iOS one can 'quit' the app by swiping up on the app switcher yet message.
Press these three keys together: Option, Command, and Esc (Escape). This is similar to pressing Control-Alt-Delete on a PC. Or choose Force Quit from the Apple () menu in the upper-left corner of your screen.
Select the app in the Force Quit window, then click Force Quit.
Mac Quit Application
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Force Quit Mac Apps
You can also force the Finder to quit, if it stops responding. Select Finder in the Force Quit window, then click Relaunch.
If none of your apps are responding, you can force your Mac to restart.
You can also force an app to close on your iPhone, iPad, or iPod touch.