As you may have gathered from the discussion of the Applications folder in the previous chapter, applications are computer programs designed for various purposes. Applications appear as icons on the desktop just like folder and files, and can be worked with in the same way.
To launch an application, locate its icon in the Applications folder (or wherever it may have been saved), and double-click it. (Note that some applications' icons appear in the Dock as well as in a folder on your desktop. You can launch them by clicking on their docked icons.) While an application is opening, its icon will appear to bounce in the Dock until it is ready for use. (At the end of this chapter we will talk about how to use a special kind of application that was written to operate in an older Mac operating system.)
Opening Unrecognized Files
If you attempt to double-click a document that the system does not recognize, Mac OS X warns you that there is "no application available to open the document." If you're sure that a program on your system is capable of viewing the file, select the Choose Application option. You are prompted to choose the application that can open the file.
By default, the system tries to guess the best application for the job ”but sometimes it fails. If the system doesn't allow you to pick the appropriate application, change the selection in the Show pop-up menu to read All Applications rather than Recommended Applications.
Force-Quitting Applications with the Process Manager
A feature that's sometimes necessary when using applications is Force Quit, which exits a program that has stopped responding. In Mac OS X, the Option-Command-Esc keystroke brings up a process manager that contains a list of running applications. Applications that the system deems to have stopped responding are marked in red. To force an application to close, choose it in the list and click the Force Quit button.
You can also access the Force Quit feature from the Apple menu, or by opening the pop-up Dock menu for a running application and pressing the Option key to toggle the standard Quit selection to Force Quit. If the system deems that an application has stopped responding, a Force Quit option appears in the Dock pop-up menu.
If the Finder seems to be misbehaving, you can choose it from the application list. The Force Quit button becomes the Relaunch button, enabling you to quit and restart the Finder without logging out.