How to Rename Icons in Mountain Lion
If an icon in OS X Mountain Lion is locked or busy (the application is currently open), or if you don’t have the owner’s permission to rename that icon, you can’t rename it. Similarly, you should never rename certain reserved icons (such as the Library, System, and Desktop folders).
To rename an icon, you can either click the icon’s name directly (don’t click the icon itself, because that selects the icon) or click the icon and press Return (or Enter) once.
Either way, the icon’s name is selected and surrounded with a box, and you can type a new name. In addition, the cursor changes from a pointer to a text-editing I-beam. An I-beam cursor is the Mac’s way of telling you that you can type now.
At this point, if you click the I-beam cursor anywhere in the name box, you can edit the icon’s original name. If you don’t click the I-beam cursor in the name box but just begin typing, the icon’s original name is replaced by what you type.
If you’ve never changed an icon’s name, give it a try. And don’t forget: If you click the icon itself, the icon is selected, and you won’t be able to change its name. If you do accidentally select the icon, just press Return (or Enter) once to edit the name of the icon.
One last thing: If you have two or more icons you want to move to a new folder, select the items and choose File→New Folder with Selection, press Command+Control+N, or right-click or Control-click one of the selected items and choose New Folder with Selection.
All three techniques will create a new folder, move the selected icons into it, and even selects the name of the new folder (which will be New Folder with Items) so you can type a new name immediately.