If a program on your Apple computer stops responding, you may need to force the application to close in order to resume your computer's functionality. When you end a task on an Apple computer, it is known as a "force quit." A force quit does not allow you to save your data, so any unsaved work will be lost when you quit the application.
Place your computer cursor over the Apple logo in the upper-left corner of the screen. Click on it to reveal the Apple drop-down menu.
Select "Force Quit" from the drop-down menu. This will prompt a display window to appear on your screen with a list of all applications that are running on your computer.
Click on the unresponsive application and confirm that you want to force quit the application. Your Apple computer will force the unresponsive program to close. If you want to resume working in the program, you will need to reopen it.