How to Protect Your Mac OS X Snow Leopard’s Files
The Info dialog on Mac OS X Snow Leopard gives you the chance to protect your files and folders by locking them. Locking prevents accidental deletion or editing. By locking a file, you allow it to be opened and copied ¯ but not changed, renamed, or sent to the Trash. Locked items appear in the Finder with a small padlock attached to the icon.
To lock or unlock a file, you have to have ownership of the file. On a Mac where you’ve configured only one administrator account, you should already have ownership.
If you’re considering changing the ownership of a system-owned file, don’t do it. You could throw a serious monkey wrench into your Snow Leopard system.
To lock a file, follow this procedure:
Display the Info dialog for the item by Command+I or choosing File→Get Info.
Select the Locked check box to enable it.The Locked check box is in the General section of the Info dialog.
Close the Info dialog to save your changes.