Microsoft KB Archive/843541

= Your computer stops responding when you use a smart card to log on to Windows XP =

Article ID: 843541

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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Important This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry



SYMPTOMS
When you enter your smart card personal identification number (PIN) to log on to a computer that is running Microsoft Windows XP, the computer stops responding when the desktop is displayed.



CAUSE
This problem occurs when you replace the Microsoft Graphical Identification and Authentication (GINA) DLL (Msgina.dll) with a third-party Msgina.dll, a custom Msgina.dll, or a pass-through &quot;stub&quot; Msgina.dll. When this Msgina.dll returns WLX_SAS_ACTION_LOCK_WKSTA immediately after the WlxLoggedOutSAS function is called, Winlogon enters a race condition and stops responding.



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

The P1 version of this P2 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.

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.

Microsoft Windows XP Service Pack 1
  Date         Time   Version           Size     File name --  21-Aug-2004  18:54  5.1.2600.1579     398,848  Licdll.dll 21-Aug-2004 18:34  5.1.2600.1586     482,816  Winlogon.exe

Microsoft Windows XP Service Pack 2
  Date         Time   Version           Size     File name --  21-Aug-2004  18:39  5.1.2600.2508     502,784  Winlogon.exe

To enable this hotfix, you must add the registry entry AlwaysStartSCThread to the following registry subkey:

. This entry takes two values: 1 and 0. To enable this hotfix, you must set AlwaysStartSCThread to 1. To disable this hotfix, you must set AlwaysStartSCThread to 0.

Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

Follow these steps, and then quit Registry Editor:  Click Start, click Run, type regedit, and then click OK. Locate and then click the following key in the registry:

 

 On the Edit menu, point to New, and then click DWORD Value. Type AlwaysStartSCThread, and then press ENTER. On the Edit menu, click Modify.</li> Type 1, and then click OK.</li></ol>

<div class="status_section">

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

<div class="moreinformation_section">

MORE INFORMATION
For additional 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

Keywords: kbqfe kbhotfixserver kbwinxpsp3fix kbwinxppresp3fix kbfix kbbug KB843541

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