ARCHIVED: In Mac OS X, what is the Classic environment, and how do I activate it?

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Note: The Classic environment is not supported in Mac OS X 10.5 and later, nor will it work on Intel-based Macs.

Mac OS X is more robust than previous versions of Mac OS, but it is not compatible with some older Mac programs. The Classic environment involves Mac OS 9 running as an application within some versions of Mac OS X, allowing you to use your older applications. However, applications running in the Classic environment cannot take advantage of the new features in Mac OS X, such as protected memory. Thus, when one Classic application crashes, it frequently causes all other Classic applications, as well as the Classic environment itself, to crash.

To run the Classic environment, you must have Mac OS 9.1 or later installed on your computer and selected in the Mac OS X Classic system preference panel. To activate the Classic environment in Mac OS X:

Log into Mac OS X.
From the Apple menu, select System Preferences....
In System Preferences, from the View menu, select Classic.
In the Classic system preference window, click the Start/Stop tab.
If no system folder is selected, under "Select a system folder for Classic:", choose your Mac OS 9 system folder.
If you would like Classic to start automatically when you log into your account, check Start Classic when you login.

Once you have set up the Classic environment, you can start it by clicking Start.