A.8. Uninstalling Mac OS X 10.5
There isn't any easy way to remove Mac OS X Leopard if you decide that you don't like
The chief problem is that thousands of its pieces are invisible. Even if you start up the
Mac from another disk and then drag all the visible Mac OS X folders to the Trash, you'll
leave behind many megabytes of software crumbs that you can't see.
So if you want to retreat to something earlier, back up the data that's worth preserving—
mainly, your Home folder and Applications folder—and then erase the hard drive or
partition and reinstall the operating system that you prefer.