Macs and OS X have a “it just works” reputation, but even the best operating systems can have problems, with apps occasionally freezing. When this happens, standard methods of quitting an app may no longer work, and you may feel that a forced reboot is necessary in order to close or reset that frozen app. But if it’s just a particular app that is frozen, and OS X remains responsive behind the frozen app, you may want to try to force quit the misbehaving app. Here are five ways to force quit an app in OS X.
Normally, when you right-click on a running application in the OS X Dock, you see an option to “Quit.” This may not work with a frozen app, however. To force quit an app, hold the Option key on your keyboard while you right-click on the app’s Dock icon and you’ll see that “Quit” is now “Force Quit.” Click it to force quit the app.
Be sure to note that there’s no warning when you force quit an app, and that the usual “save” prompts don’t appear before the app is closed. Therefore, be careful when you make your selection, and double check to ensure you’re force quitting the correct frozen app. If you accidentally force quit an app you’re working in, you’ll lose any unsaved data or changes.
The Force Quit Window
OS X has a special window dedicated to handling apps that need to be force quit. You can access this window two ways, first, by clicking the Apple logo in the Menu Bar and selecting Force Quit. Alternatively, you can bring up this same window by using the keyboard shortcut Command-Option-Escape.
The window will display all running applications, and identify with red text any apps that are “not responding.” Just highlight an app and click the Force Quit button to quit it. As mentioned above, there’s no warning when you force quit an app, so be careful as you make your selection.
The Activity Monitor app offers a wealth of information about the current status of your Mac, its resources, and your applications, but it also allows you to force quit any frozen apps. Just locate the app in the processes list (hint: you can use the search box in the upper-right portion of the window to filter the list), select it to highlight it, and then press the X button in the upper-left part of the window.
You’ll be presented with two options: Quit and Force Quit. If possible, try Quit first, as this will attempt to gracefully quit the application and preserve user data. If that fails, use Force Quit, which will act the same way as the steps mentioned above.
The ‘Kill’ Command in Terminal
If you prefer a command line method to dealing with unresponsive apps, you can use the ‘kill’ command in Terminal. To use this method, you’ll need to determine the app’s Process ID (PID), a numeric value that OS X uses to keep track of each unique application. The easiest way to find an app’s PID is via Activity Monitor, where it will be listed in the PID column. If you’re using Activity Monitor to find the PID, however, you might as well use it to force quit the app, as described previously.
Instead, you can use the ‘top’ command to generate a list of running processes right in Terminal. You can use modifiers to order the list by user-defined criteria (see this manual page for all of the options). If your app is frozen, there’s a good chance that it’s eating up CPU resources, so a good sorting method to start with is ‘cpu.’ Open a new Terminal window and type the following command:
top -o cpu
A list of all running applications and processes will appear in Terminal, ordered by current CPU usage. Let’s use iTunes as the example. It’s listed at the top (because it’s currently consuming CPU resources) and its process ID is 5472 (note: PIDs are unique to each circumstance, and OS X generates a new PID each time an application is run. That means that the PID will change each time an app is launched, and it’s almost certain that iTunes on your own Mac will have a different PID).
With the process ID now identified, press Q to quit top, or open a new Terminal session, and type the following to force quit the app:
In our iTunes example, we’d type:
Press Return to execute the command and your app will be force quit.
You can directly force quit an app via a keyboard shortcut, without any of the intervening steps mentioned in the previous methods above. This may therefore seem to be the best and most obvious method, but there’s a reason it’s listed here last. Using the keyboard shortcut below will immediately force quit the active, or foremost, application. The problem is that it’s very easy to lose track of which app is active, especially when dealing one or more frozen or unresponsive apps. Therefore, this method is the most risky from a data loss perspective, as it’s far more likely that a user will make a mistake and inadvertently force quit the wrong app.
But, if you understand this risk and are careful, this force quit shortcut is the fastest method. To use it, make sure the frozen app is active and press and hold Command-Option-Shift-Escape (you’ll notice that this is simply the Force Quit Window shortcut with the Shift key modifier thrown in). As with other force quit methods, the active application will immediately be force quit.
Sometimes hardware issues or major OS X bugs cause so much instability that the only way to get your Mac up and running again is to reboot. Absent those relatively rare circumstances, however, you should be easily able to control any frozen or misbehaving apps by force quitting them via one of the methods above. Just be sure to save your work when possible, and double-check your steps to avoid quitting the wrong app.
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