TAPI-based applications stop responding, and you cannot disconnect telephone calls on a Windows XP-based telephony server

On a Windows XP-based telephony server, Telephony Application Programming Interface (TAPI)-based applications stop responding (hang). Additionally, you cannot disconnect telephone calls even though the remote party has disconnected from the call.

This problem occurs if the following conditions are true:

• A telephone call is in the process of being disconnected.
• The server is located in a large telephony server call center.
• The telephony server has more than one CPU.

This problem occurs because of a deadlock condition between the lineClose function call and the lineDeallocateCall function call.

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.

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, submit a request to 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.

Prerequisites

To apply this hotfix, you must have Windows XP Service Pack 2 (SP2) or a later service pack installed.

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

Restart requirement

You must 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 item in Control Panel.

Windows XP with Service Pack 2, x86-based versions

Windows XP with Service Pack 3, x86-based versions

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

For more information, click the following article numbers to view the articles in the Microsoft Knowledge Base: For more information about Microsoft Telephony, visit the following Web site: For more information about TAPI applications, visit the following Web site: