Windows cannot write to a Mac formatted floppy disk (without help), but Mac can read a Windows formatted floppy disk if it's formatted in FAT and not NTFS. While Macs and PCs use the size floppy disks, the file system format is different. Insert “USB Floppy Disk Drive Device Driver” CD-ROM disc into the CD-ROM drive on your PC. Connect the USB floppy disk drive to the USB connector on your computer.