If an application on your Mac becomes unresponsive, you may need to forcefully terminate the app. This is called "Force Quitting" it, and there are a handful of ways to access this tool in Mac OSX:

  • One option is to hit Command-Alt-Esc on the keyboard, which will bring up the Force Quit window, allowing you to select an app and Force Quit it by clicking the button on the bottom right:

  • Another option is to go to the application on the dock, right-click it (Command+click if your mouse only has left click), and select "Quit" (which will become "Force Quit" if the app is unresponsive):

  • Another option is to select "Force Quit <app>" under the Apple symbol on the menu bar at the top of the screen:

All of these options will allow you to quickly kill any programs that are hanging, letting you get back to work quickly.