Microsoft KB Archive/892520

= The NTVDM CommsAutoClose setting does not work in Windows XP =

Article ID: 892520

Article Last Modified on 8/29/2007

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APPLIES TO


 * Microsoft Windows XP Professional
 * Microsoft Windows XP Home Edition

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SYMPTOMS
Assume the following scenario. In Microsoft Windows XP, you run a 16-bit application for which the following conditions are true:
 * The application is running in a Windows NT Virtual DOS Machine (NTVDM) environment.
 * The application accesses a COM port on the computer.

In this scenario, you notice that another 16-bit or 32-bit application cannot access the same COM port until you quit the first 16-bit application.



CAUSE
This problem occurs because the NTVDM CommsAutoClose setting does not work in Windows XP. Specifically, the code that handles the CommsAutoClose registry entry is not included in Windows XP.



Hotfix information
A supported hotfix is now available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next service pack that contains this hotfix.

To resolve this problem, submit a request to Microsoft Online Customer Services to obtain the hotfix. To submit an online request to obtain the hotfix, visit the following Microsoft Web site:

http://go.microsoft.com/?linkid=6294451

Note If additional issues occur or any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. To create a separate service request, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Prerequisites
You must have Windows XP Service Pack 1 (SP1) or Windows XP Service Pack 2 (SP2) installed before you apply this hotfix.

Restart requirement
You do not have to restart the computer after you apply this hotfix.

Hotfix replacement information
This hotfix does not replace any other hotfixes.

File Information
The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

Windows XP Service Pack 1   Date         Time   Version            Size    File name --  01-Dec-2004  06:03  3.10.0.103         92,224  Krnl386.exe 01-Dec-2004 05:56                     33,840  Ntio.sys 01-Dec-2004 05:56                     34,560  Ntio404.sys 01-Dec-2004 05:56                     35,648  Ntio411.sys 01-Dec-2004 05:56                     35,424  Ntio412.sys 01-Dec-2004 05:56                     34,560  Ntio804.sys 19-Jan-2005 03:37  5.1.2600.1620     396,800  Ntvdm.exe 04-Jun-2004 00:43  5.1.2600.1562     245,760  Wow32.dll Windows XP Service Pack 2   Date         Time   Version            Size    File name 19-Jan-2005 03:12  5.1.2600.2598     420,352  Ntvdm.exe



STATUS
Microsoft has confirmed that this is a bug in the Microsoft products that are listed in the &quot;Applies to&quot; section.



MORE INFORMATION
For more information, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

For more information about the same problem in Microsoft Windows 2000, click the following article number to view the article in the Microsoft Knowledge Base:

301183 The NTVDM CommsAutoClose setting does not work in Windows 2000

Keywords: kbhotfixserver kbqfe kbwinxpsp2fix kbwinxppresp2fix kbfix kbbug kbpubtypekc KB892520

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