A memory leak occurs when the MessageBeep function is called in Windows Vista

When you run an application that calls the MessageBeep function on a Windows Vista-based computer, several system page table entries (PTEs) are leaked. Under most circumstances, this minor leak is not noticeable. However, if the MessageBeep function is frequently or repeatedly called, this leak may cause the computer to stop responding (hang).

Note You can view the system PTE usage in Performance Monitor. To do this, add the Free System Page Table Entries counter to Performance Monitor.

In this situation, the port class driver maps a buffer. However, this driver does not always then unmap the buffer as expected. Therefore, the system PTEs that are used to map the buffer are leaked.

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.

Prerequisites

No prerequisites are required.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other previously released hotfixes.

Registry information

To use this hotfix, you do not have to make any changes to the registry.

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 Vista, x86-based versions

Windows Vista, x64-based versions

Windows Vista, IA-64-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 the MessageBeep function, visit the following Microsoft Web site: For more information, click the following article number to view the article in the Microsoft Knowledge Base: