DOCUMENT:Q110406  22-NOV-1999  [msdos]
TITLE   :MS-DOS 6.2 Step-Up Fails with McAfee V-Scan
PRODUCT :Microsoft Disk Operating System
PROD/VER:MS-DOS:6.2
OPER/SYS:
KEYWORDS:

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The information in this article applies to:

 - Microsoft MS-DOS operating system version 6.2 
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SYMPTOMS
========

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.

   -or-

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

   <filename>

CAUSE
=====

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.

RESOLUTION
==========

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.

MORE INFORMATION
================

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.

Additional query words: 6.20 Macafee mcaffee v-shield

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Keywords          :  
Technology        : kbMSDOSSearch kbMSDOS620
Version           : MS-DOS:6.2

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