This workaround involves using a disk sector editor to modify the media descriptor byte on the floppy disk. Warning: This workaround is for advanced users only. To resolve this problem, re-format the floppy disk with Windows 98, Windows Millennium Edition, Windows NT, Windows 2000, Windows XP, or Windows Server 2003. The media descriptor byte is located in the BPB of the boot sector at offset 21 (15h) and in the first byte of each FAT on the disk. Therefore this problem does not occur with these older operating systems. With MS-DOS and Windows 95, you do not have to set the media descriptor byte. The media descriptor indicates the type of medium currently in a drive. Older product disks may also not have the media descriptor byte. Some older preformatted floppy disks do not contain a media descriptor byte.

This problem occurs on disks that do not contain a media descriptor byte in the BIOS parameter block (BPB) of the boot sector. The same disk may work correctly with MS-DOS or Windows 95, or after you re-format the disk with Windows 98, Windows Millennium Edition, Windows NT, Windows 2000, Windows XP, or Windows Server 2003. STOP: The disk media is not recognized, it may not be formatted.

Format a floppy disk