MS-DOS 6.2 Step-Up Fails with McAfee V-Scan (110406)

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

This article was previously published under Q110406


MS-DOS 6.2 Step-Up may generate one of the following messages and fail if you try to run it on a system on which the McAfee V-Scan Checksum option /ag or /av has been used:

In order to run the MS-DOS 6.2 single-disk upgrade, you must already have MS-DOS 6.0 installed on your system.


Cannot Update File. Setup could not update the following file to MS-DOS 6.2:



The Checksum feature adds either 10 or 52 extra bytes to the size of executable files. The /ag switch adds 52 bytes to executable files and allows validation and recovery of infected files. The /av switch adds 10 bytes to the files and allows a validation check only. Either Checksum option may cause MS-DOS 6.2 Step-Up to fail because Step-Up does not recognize the system and executable files it attempts to update.


The /ag option can be reversed by running the following command:
   scan /rg
The /av option can be reversed by running the following command:
   scan /rv
Disabling Checksum by using the above switches should return the files to their original sizes and allow MS-DOS Step-Up to upgrade the necessary files. If MS-DOS Step-Up still fails, recopy the MS-DOS 6.0 system files from the original MS-DOS 6.0 disks to the bootable partition of the hard disk drive. If this is not successful, a reinstallation of MS-DOS 6.0 may be necessary.


For more information, contact McAfee Associates.

The McAfee V-Scan is manufactured by McAfee Associates, a vendor independent of Microsoft; we make no warranty, implied or otherwise, regarding this product's performance and reliability.

Modification Type: Major Last Reviewed: 11/22/1999
Keywords: KB110406