New nodes cannot join the mesh after a custom resolver uses the CustomPeerResolverService class in the .NET Framework 3.0

Applies to: .NET Framework 3.5 Service Pack 1Windows 7Windows Server 2008 R2


Consider the following scenario:
  • Some Windows Communication Foundation (WCF) peer channel clients use a custom resolver to obtain the IP addresses of the peer nodes in a mesh. The mesh has various peer nodes.
  • The custom resolver uses the CustomPeerResolverService class in the Microsoft .NET Framework 3.0. 
  • An update operation occurs on a registered node. A new registration operation occurs on another peer node.

In this scenario, the custom resolver may stop responding. Therefore, the new nodes cannot join the mesh.


This issue occurs because of an issue in the CustomPeerResolverService class.

When the update operation occurs, it may be transformed into a registration operation. Therefore, two threads in the custom resolver try to obtain a read and write lock at the same time.


Hotfix information

A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

To resolve this problem, contact Microsoft Customer Support Services to obtain the hotfix. For a complete list of Microsoft Customer Support Services telephone numbers and information about support costs, visit the following Microsoft website:Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.


To apply this hotfix, you must have the Microsoft .NET Framework 3.5 Service Pack 1 (SP1) installed on a computer that is running Windows 7 or Windows Server 2008 R2.

Note The Microsoft .NET Framework 3.5 SP1 includes the Microsoft .NET Framework 3.0 Service Pack 2 (SP2).

Restart requirement

You do not have to restart the computer after you apply this hotfix if the affected files are not being used.

We recommend that you close all .NET Framework applications before you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix. 

File Information

The global 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 7
File nameFile versionFile sizeDateTimePlatform
Servicemodel.mofNot Applicable85,11325-May-201122:33x86
Servicemodel.mof.uninstallNot Applicable89610-Jun-200921:14x86
For all supported x64-based versions of Windows 7 and of Windows Server 2008 R2
File nameFile versionFile sizeDateTimePlatform
Servicemodel.mofNot Applicable85,11325-May-201122:32x64
Servicemodel.mof.uninstallNot Applicable89610-Jun-200920:30x64
For all supported IA-64based versions of Windows Server 2008 R2
File nameFile versionFile sizeDateTimePlatform
Servicemodel.mofNot Applicable85,11325-May-201122:25IA-64
Servicemodel.mof.uninstallNot Applicable89610-Jun-200920:35IA-64


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

More Information

For more information about WCF peer channel, visit the following MSDN website: