In OS X, there are two ways to move or copy icons from one place to another: by dragging them and by using the Copy and Paste commands.
You can drag icons from one folder to another, from one drive to another, from a drive to a folder on another drive, and so on. (When you’ve selected several icons, drag any one of them; the others tag along.) As you drag, you see the ghostly images of all the selected icons moving with your cursor. And the cursor itself sprouts a circled number that reminds you how many files you’re moving.
You can tell that the copying is under way even if the progress bar is hidden. A tiny progress bar appears right on the icon of the copied material in its new home. You can cancel the process either by pressing ⌘-period or by clicking the in the progress window.
Understanding when the Mac copies a dragged icon and when it moves it bewilders many a beginner. However, the scheme is fairly simple when you consider the following: