Apple Macintosh Performa 570 series - Manual (Page 63)

Your Macintosh can’t read a floppy disk.
If you see a message that a floppy disk is unreadable, try one of the following:
m If the disk has never been used, you may simply need to initialize it. For
instructions, see the “Disks” topic of Macintosh Guide, available in the
Guide (h) menu.
m The disk may be damaged. See “Repairing a Damaged Disk” later in this
chapter for information on testing and repairing disks.
If you are trying to use a DOS disk, consider the following:
m The disk may have been formatted incorrectly on a DOS computer. On
DOS computers it’s possible to format a standard double-sided disk in a
high-density (1440K) format, and vice versa. Disks formatted in this way
cannot be read by a Macintosh computer.
When formatting disks on a DOS computer, always format standard
double-sided disks in the 720K format. Always format high-density disks
in the 1440K format.
If a disk has been formatted incorrectly, use a DOS computer to copy its
contents onto another disk that has been properly formatted.
55 Troubleshooting