FORMAT May Allow Access to Unformatted Drives (82272)

The information in this article applies to:
    Microsoft MS-DOS operating system 5.0
    Microsoft MS-DOS operating system 5.0a
    Microsoft MS-DOS operating system 6.0

This article was previously published under Q82272


If, while attempting to format a fixed disk, you terminate the MS-DOS FORMAT command by pressing N (No) at the

Proceed with Format (Y/N)
message, MS-DOS may allow access to a fixed disk drive even if it has never been properly formatted.

A drive accessed in this manner isn't stable for use with MS-DOS, and may report large numbers of lost allocation units or other problems when you run the MS-DOS CHKDSK command.


Responding N to the "Proceed with Format (Y/N)?" message causes FORMAT to incorrectly set the drive's SYSTEM (as reported by FDISK) to FAT12 or FAT16, allowing access to the unformatted drive.


Microsoft has confirmed this to be a problem in MS-DOS versions 5.0, 5.0a, and 6.0. This problem was corrected in MS-DOS FORMAT version 6.2.


To return the drive to its inaccessible status, simply reboot the machine. To prepare the drive for use with MS-DOS, use the FORMAT command to format the drive.

Modification Type: Major Last Reviewed: 10/13/2003
Keywords: KB82272