If you are still unsuccessful, the drive may need professional repair.

To see if this is the problem, try saving or copying files onto another floppy disk. Test it with Disk First Aid, following the instructions in 'Repairing a Damaged Hard Disk or Floppy Disk' in Chapter 13. Throw away items on the disk that you no longer need, or save the files on a different disk. Unlock it by sliding the tab at the corner of the disk so that it covers the hole. You can't save or copy files onto a floppy disk. If none of these solutions works, take the computer or disk drive to your Apple-authorized service provider to have the disk removed. Locate the small hole near the disk drive's opening, and carefully insert the end of a large straightened paper clip into it.If the disk isn't ejected, hold down the button on your trackpad or other pointing device while you turn the computer on again. Hold down the X and Shift keys and press the number 1 key on your keyboard.

If you can't eject a floppy disk in the usual way, by selecting the disk's icon and choosing Put Away from the Special menu or by dragging the disk's icon to the Trash, try the following in order:

Mac format floppy disk