User Tip #126: Error using preformatted disks - STOP: The disk media is not recognized, it may not be formatted.

Hits: Failed to execute CGI : Win32 Error Code = 3

Some preformatted disks do not have a valid descriptor byte. NT strictly follows DOS descriptor byte standards. A missing descriptor byte will not cause DOS a problem. NT will generate the message:

STOP: The disk media is not recognized, it may not be formatted.

This is sometimes confused as a virus symptom. The same disk would work for DOS, WFW, and Win9x. To resolve the problem, simply format the diskette using NT. Kinda ruins the value of preformatted disks.

Background info taken from Q140060:

The media descriptor byte is located in sector 0 of the diskette at offset hex 15, and looks has this data:

      addr  data:
      0000  EB 3C 90 4D 53 44 4F 53 35 2E 30 00 02 01 01 00
      0010  02 E0 00 40 0B F0 09 00 12 00 02 00 00 00 00 00

Valid media descriptor bytes for MS-DOS:

      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 

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