Place your palm on the mouse, and let me read your past ... Ah, it is clear that you have had to reinstall the System Software on your Mac! When you want to reinstall the System Software, you have your choice of installing the software in place, or doing a clean install . When you chose to do a clean install, the installer will create a brand new System Folder, and rename your old System Folder "Previous System Folder" . The Previous System Folder will lose its blessed System Folder icon, and look just like any other folder on the hard drive. Although this folder has a glorious past life, its future is bleak. After salvaging important preference files and extensions, it is best to trash the Previous System Folder.