When you run an application that uses a timer queue on a Windows XP-based computer, the application may stop responding, or an access violation may occur in the application. When this issue occurs, you have to restart the application.
This timing issue occurs when a timer creation asynchronous procedure call (APC) runs after the timer deletion APC is called.
When a timer queue is created, the following process occurs:
Windows XP creates a timer queue.
Windows XP creates a timer queue timer. When the request to create the timer is called, an APC routine to add the timer is posted.
The application runs some operations.
Windows XP deletes the timer queue timer. When the request to delete the timer queue timer is called, an APC routine to delete the timer is posted.
Windows XP deletes the timer queue.
If the application that is using the timer queue finishes step 3 very quickly or if it does nothing in step 3, the APC routine to add a timer might be called after step 4 and step 5 are called. In this case, the APC routine to add the timer discovers that the queue has been marked as deleted. Therefore, the APC routine to add the timer deletes the timer in the queue. However, when the APC routine to delete the timer runs, the routine tries to delete the timer that has already been freed. Therefore, this issue occurs.
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.
To apply this hotfix, you must have Windows XP Service Pack 2 (SP2) or Windows XP Service Pack 3 (SP3) installed on the computer.
You have to restart the computer after you apply this hotfix.
Hotfix replacement information
This hotfix does not replace any other previously released hotfixes.
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 SP2, x86-based versions
Windows XP with SP3, 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 about timer queues, visit the following Microsoft Web site: