Apple Macintosh Performa 6100 Series - Manual (Page 67)

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.
m If the disk is a high-density disk previously used on another computer, the
disk may have been formatted incorrectly as an 800K disk rather than as a
1440K (high-density) disk. If so, use the other computer to copy the disk’s
contents onto a properly formatted disk.
If you are trying unsuccessfully to use a DOS floppy disk, consider the
following:
m When formatting floppy disks on a DOS computer for use in a Macintosh,
users need to format standard double-sided disks as 720K disks and high-
density disks as 1440K disks. Because DOS computers allow standard
double-sided disks to be formatted in 1440K format and high-density disks
to be formatted in 720K format, it’s possible that your disk has been given
a format that won’t work in a Macintosh.
If you think your DOS floppy disk might have a format that doesn’t work
in a Macintosh, use a DOS computer to copy the contents of your DOS
floppy disk onto another DOS floppy disk that has been properly formatted
for use in a Macintosh.
57 Troubleshooting