JSI Tip 1861. 'STOP: The disk media is not recognized, it may not be formatted'.

You receive the subject message when you attemp to access a floppy disk.

Windows NT requires a media descriptor byte. Some preformatted diskettes don't have a media descriptor byte.

The workaround is to format the diskette in Windows NT.

Some programs, such as NORTON DISKEDIT can change the media descriptor byte, which is located at byte 21 (0x15) of sector 0, counting from 0. Here is a table of media descriptor bytes:

    Byte   Capacity   Media Size and Type   -------------------------------------------------   F0     2.88 MB    3.5-inch, 2-sided, 36-sector   F0     1.44 MB    3.5-inch, 2-sided, 18-sector   F9     720K       3.5-inch, 2-sided, 9-sector   F9     1.2 MB     5.25-inch, 2-sided, 15-sector   FD     360K       5.25-inch, 2-sided, 9-sector   FF     320K       5.25-inch, 2-sided, 8-sector   FC     180K       5.25-inch, 1-sided, 9-sector   FE     160K       5.25-inch, 1-sided, 8-sector   FE     250K       8-inch, 1-sided, single-density   FD     500K       8-inch, 2-sided, single-density   FE     1.2 MB     8-inch, 2-sided, double-density   F8     -----      Fixed disk