The Data Collector Set may not start on a computer that is running Windows Server 2008 or Windows Vista

Consider the following scenario:

• You create a new Data Collector Set by using the Performance Monitor tool on a computer that is running Windows Server 2008 or Windows Vista.
• You add some performance counters to the created Data Collector Set.
• You schedule the new Data Collector Set to run regularly.

In this scenario, the Data Collector Set may not start.

This issue occurs because of an access violation exception.

The expected behavior is that the PdhExpandWildCardPath function returns the path list together with both NULL characters in all scenarios.

However, when the length of the input buffer is one short of the required length, the PdhExpandWildCardPath function returns success and returns the path list together with only one NULL character. This behavior causes the calling function to trigger an access violation exception.

The data collector for the performance log also calls the PdhExpandWildCardPath function. Therefore, when the access violation exception occurs, the data collector cannot start.

To resolve the issue, install this hotfix. After you install this hotfix, the PdhExpandWildCardPath function returns the code PDH_MORE_DATA if the length of the input buffer is one short of the required length.

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 the problem described in this article. 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

To apply this hotfix, the computer must be running one of the following operating systems:

• Windows Vista Service Pack 1 (SP1)
• Windows Vista Service Pack 2 (SP2)
• Windows Server 2008
• Windows Server 2008 Service Pack 2 (SP2)

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other 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.

For all supported x86-based versions of Windows Server 2008 and of Windows Vista SP1

For all supported x86-based versions of Windows Server 2008 SP2 and of Windows Vista SP2

For all supported Itanium-based versions of Windows Server 2008

For all supported Itanium-based versions of Windows Server 2008 SP2

For all supported x64-based versions of Windows Server 2008 and of Windows Vista SP1

For all supported x64-based versions of Windows Server 2008 SP2 and of Windows Vista SP2

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 number to view the article in the Microsoft Knowledge Base:

Additional file information for Windows Server 2008 and for Windows Vista

Additional files for all supported x86-based versions of Windows Server 2008 and of Windows Vista

Additional files for all supported Itanium-based versions of Windows Server 2008

Additional files for all supported x64-based versions of Windows Server 2008 and of Windows Vista

For more information about the PdhExpandWildCardPath function, visit the following Microsoft Web site: