Windows users will be very familiar with the classic CTRL+ALT+DELETE key combination, the measure of last resort when an application has become unresponsive. While OS X, and its predecessors are very stable operating systems, even Mac owners will sometimes experience the need to close an app manually after it has stopped working properly.
So if you're finding that instead of iTunes searching for that cool alt rock album you want to listen to, you're staring at a spinning beach ball, then help is at hand. There are a few different ways to close apps, from the Force Quit command to the more extreme measure of rebooting your machine entirely.
Here we'll show you how to find the problematic programs and shut them down, without the need to resort to the power button. If you're finding that apps are becoming unresponsive on a regular basis, and that it's not always the same one, then it might be worth backing up all your data and doing a clean install of OS X (you can read how to do that here). It's a rather nuclear option, but could save you a lot of headaches in the long run.
Read next: 5 steps (and 8 checks) to fix a frozen Mac
How to force quit on Mac: Fix unresponsive apps by using the Force Quit option in the Dock
If an app has become unresponsive, then there's a good chance that trying to place your mouse pointer over the menu bar at the top of the screen will result in a spinning beach ball that doesn't allow you to select any options. You can of course give the app some time to resolve its issue, but if the problem persists then the app will need closing and launching again.
Go to the Dock at the bottom of the screen and find the icon for the app, then right click (or ctrl+click) to bring up the contextual menu. At the bottom of this list is the Quit option. Click this and hopefully the app will close. If not, repeat the process, but when the menu appears hold down the alt key and the Quit option changes to Force Quit - a more powerful way to close the app. Select this and the program should close immediately.
There is another way to access the Force Quit command; if you change to an app that is working fine, then go up to the Apple icon in the top left of your screen, and click on it, you can select the Force Quit option from the drop-down list.
How to force quit on Mac: Force Quit on a Mac using the keyboard
Another way to force quit an app is to hold down the cmd+alt+esc keys. Within the list that appears is every app currently running on your system, and the one you're having problems with most likely has 'Not Responding' in brackets next to it. Highlight the app, then click the Force Quit button in the bottom of the window. Now try relaunching the app to see if the problem has been resolved.
How to force quit on Mac: What to do when you can't leave the app
In severe cases, you'll find that you can't actually escape from the app itself to perform the above commands. If this is the case then you still have a command you can use. Simply hold down the cmd+alt+shift+esc buttons and OS X will close whichever app is currently the active one on your screen.
How to force quit on Mac: Use the Activity Monitor
If you're experiencing problems on your system, say the spinning beach ball is appearing more than normal, then one way to see what's happening is using the built-in Activity Monitor. You'll find this useful tool by going to the Finder and navigating to Applications>Utilities>Activity Monitor. When launched this tool displays all the apps and services that are using the CPU, Memory, and Network among other things.
Double clicking on any app will bring up a separate window with even more information about the app and its current demands. From here you can choose to Sample the app, which gives you a report of its activities over a short period of time, but this is quite a technical procedure and the results are unintelligible for most people. The more useful command is the Quit button, which will of course close the app.
How to force quit on Mac: What to do when your computer is frozen
Sometimes an app can get into trouble and cause your entire system to freeze. While these cases are rare, they do happen and in the end the only option left to you is to hold down the power button on your Mac for several seconds. Normally when you press the power button a message is sent to your system telling it that you want to close it down. The system then usually responds by putting the machine to sleep.
Holding the button down longer will give you a dialog box with various options such as Restart, Sleep, or Shut Down. But in a severe system crash, even this option might not appear. So the last resort is to hold the button down until the machine cuts off the power completely. Now, while this will allow you to reboot and get back into your Mac, because of the sudden nature of the shutdown you may find that any unsaved data will be lost. It's not perfect, but sometimes its the only way to get back up and running.