Microsoft KB Archive/941061

= Trace events in the log output are randomly lost on a Windows Vista-based computer that has the ETW trace log enabled =

Article ID: 941061

Article Last Modified on 12/27/2007

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APPLIES TO


 * Windows Vista Enterprise
 * Windows Vista Home Basic
 * Windows Vista Home Premium
 * Windows Vista Ultimate
 * Windows Vista Enterprise 64-bit Edition
 * Windows Vista Home Basic 64-bit Edition
 * Windows Vista Home Premium 64-bit Edition
 * Windows Vista Ultimate 64-bit Edition
 * Windows Vista Business
 * Windows Vista Business 64-bit Edition

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SYMPTOMS
On a Windows Vista-based computer, you enable the Event Tracing for Windows (ETW) trace log. After you extract a large .psf file, and then you exam the log output, some trace events are randomly lost. If you extract the .psf file again, you may find that a random subset of the trace events is lost.



CAUSE
This issue occurs because the event tracing session runs out of free buffers. When high event rates are processed at the same time, the disk subsystem becomes overloaded. In this case, the event tracing session randomly discards some events instead of holding the process until more buffers become available.



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 Windows Vista 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

Prerequisites
There are no prerequisites for installing this hotfix.

Restart requirement
You have to restart the computer after you apply this hotfix.

Hotfix replacement information
This hotfix does not replace a previously released hotfix.

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, x64-based versions


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



MORE INFORMATION
For more information about Event Tracing, visit the following Microsoft Web sites:

http://msdn2.microsoft.com/en-us/library/aa363668.aspx

http://msdn2.microsoft.com/en-us/library/aa363802(VS.85).aspx

For more information about how to use Event Tracing, visit the following Microsoft Web site:

http://msdn2.microsoft.com/en-us/library/aa364158(VS.85).aspx

For more information about software update terminology, 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: kbexpertiseadvanced kbfix kbqfe kbhotfixserver KB941061

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