When a System is drag-copied onto a disk rather than installed using the
Installer, the System becomes unstable. There are several symptoms:
* The System bombs often.
* The System hangs without error messages.
* Applications unexpectedly quit.
There is no way to tell which Systems have been installed using the
Installer and which have not. The best thing to do is to remove a suspect
System Folder and reinstall using the Installer application.