MS-DOS Does Not Properly Process Hard Disk Hardware Errors


Data corruption may occur when you are using an MS-DOS-based program in MS-DOS mode if your hard disk has a hardware error. Your computer is in MS-DOS mode if you started your computer with a system startup floppy disk, or if you selected Command Prompt Only from the Startup menu, or if you selected Restart in MS-DOS mode from the Shut Down Windows dialog box. It only occurs in Windows if the Performance tab of the System tool in Control Panel indicates that the disk file system is using MS-DOS Compatibility mode.


This problem can occur if MS-DOS does not process hard disk errors correctly when the hard disk is being accessed by using LBA mode (extended interrupt 13). This can cause data to be returned that has not really been read or the failure to completely write data to the disk. In either case, no failure is returned to the program.


The following files are available for download from the Microsoft Download Center:

Windows 98 and Windows 98 Second Edition (SE)

Windows Millennium Edition (Me)

The English version of this fix should have the following file attributes or later.

Windows 98

Date Time Size File name
30-Nov-2001 21:31 222,670 Io.sys

Windows 98 Second Edition

Date Time Size File name
01-Dec-2001 15:37 222,670 Io.sys

Windows Millennium Edition (Me)

Date Time Size File name
29-Nov-2001 12:29 110,080 Io.sys


Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.