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

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.

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 "stub" 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 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 software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if 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. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language. 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

Microsoft Windows XP Service Pack 2

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:

1. Click Start, click Run, type regedit, and then click OK.
2. Locate and then click the following key in the registry:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
3. On the Edit menu, point to New, and then click DWORD Value.
4. Type AlwaysStartSCThread, and then press ENTER.
5. On the Edit menu, click Modify.
6. Type 1, and then click OK.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section of this article.

For additional information, click the following article number to view the article in the Microsoft Knowledge Base: