MS-DOS Setup Displays Error: Setup Error Detected (121857)

The information in this article applies to:
    Microsoft MS-DOS operating system 6.0
    Microsoft MS-DOS operating system 6.2
    Microsoft MS-DOS operating system 6.21
    Microsoft MS-DOS operating system 6.22

This article was previously published under Q121857


When you are installing MS-DOS Upgrade or MS-DOS StepUp, the following error message is displayed:


The following disk error was detected. The listed file was not copied.

Error reading --> COMMAND.DAT

To exit Setup, press ENTER.


The Uninstall process of Setup displays the above error message when it is trying to copy C:\COMMAND.COM to A:\COMMAND.DAT on the Uninstall disk.

This error occurs when COMMAND.COM is cross-linked with another file, has allocation unit errors, or there is a bad sector on the disk.


You can correct this problem by replacing the COMMAND.COM file. Copy the COMMAND.COM file from your DOS directory over the existing COMMAND.COM file in the root directory using the following commands:

attrib -r

ren command.old

copy c:\dos\ c:\

NOTE: If the Uninstall portion of setup is bypassed by using the SETUP /G switch, the error does not occur. Also, using CHKDSK /F or SCANDISK may allow you to work around this problem.

Modification Type: Major Last Reviewed: 11/26/1999
Keywords: KB121857