Erasing, reformatting, or initializing a disk permanently deletes all of the disk's contents. Before you erase the disk, make a copy of any files you don't want to erase.

To erase a disk or erasable CD, use the Erase Disk command in the Special menu.

Help me erase a disk.

Note: When you erase a disk, the Format pop-up menu gives you choices that include Mac OS Standard (HFS) and Mac OS Extended (HFS Plus). Mac OS Standard format is compatible with all versions of the Mac OS. But Mac OS Extended is compatible only with Mac OS 8.1 or later. If you format a hard disk with Mac OS Extended format, you can't use that disk with computers that use Mac OS 8 or earlier.

For information about the formats available, open the Help menu and choose Show Balloons. Then point to the option you want to learn more about.

If you can't erase a hard disk:

•	Make sure the disk is not your current startup disk.
•	Make sure the disk is not being shared on a network. To turn off file sharing, use the File Sharing control panel. Turn file sharing off for me. Turn file sharing on for me.