Hotfix Rollup 2733955 is available for the .NET Framework 3.5 SP1 on Windows 7 SP1 and on Windows Server 2008 R2 SP1

Applies to: Microsoft .NET Framework 3.5 Service Pack 1


This article describes Hotfix Rollup 2733955 for the Microsoft .NET Framework 3.5 Service Pack 1 (SP1). This hotfix rollup provides fixes for stability, reliability, and performance issues in the .NET Framework 3.5 SP1.

This hotfix rollup is available for the following operating systems:
  • Windows 7 Service Pack 1 (SP1)
  • Windows Server 2008 R2 Service Pack 1 (SP1)

Issue that is fixed

When you install a hotfix or an update for any of the .NET Framework 2.0, .NET Framework 3.0, or .NET Framework 3.5 components on a computer that has the .NET Framework 3.5 Service Pack 1 (SP1) installed, the machine.config or web.config file may be corrupted. This problem occurs when a "configSource" attribute is used to redirect sections of the configuration file to an external configuration file.

For example, you have a machine.config file or a web.config file that contains a redirected section such as the following:
<bindingExtensions configSource="other.config" />

After a .NET Framework update is installed, there are additional entries under the "bindingExtensions" element as in the following example:
<bindingExtensions configSource="other.config" />
<add name="name1" />
<add name="name2" />

This problem causes the configuration file to be invalid. The presence of the "configSource" attribute in the "bindingExtensions" element means that there should be no child elements under "bindingExtensions" in the configuration file. Additionally, when you run a Windows Communication Foundation (WCF) application on the computer, you receive a System.Configuration.ConfigurationException exception.

After this hotfix is installed, future updates that are installed will be aware of the presence of the "configSource" attribute and refrain from changing these elements.


To work around this issue, use one of the following methods:
  • Manually remove the additional child elements as a workaround. But be aware that future updates may cause this issue to occur again if this hotfix is not applied to the system.
  • Move the configuration from the external configuration file back into the machine.config or web.config file.


Hotfix information

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

To resolve this problem immediately, 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, go to 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.


You must have the Microsoft .NET Framework 3.5 SP1 installed on one of the following operating systems to apply this hotfix:
  • Windows 7 Service Pack 1 (SP1)
  • Windows Server 2008 R2 Service Pack 1 (SP1)

Restart information

You may have to restart the computer after you apply this hotfix if any affected files are being used when you install this hotfix. We recommend that you close all the .NET Framework-based applications before you apply this hotfix to avoid having to restart the computer.

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.

For all supported x86-based versions of Windows 7 SP1
File nameFile versionFile sizeDateTimePlatform
Wfservicesreg.exe3.5.594.5825197,71226-Jul- 201213:02x86
For all supported x64-based versions of Windows 7 SP1 and of Windows Server 2008 R2 SP1
File nameFile versionFile sizeDateTimePlatform
Wfservicesreg.exe3.5.594.5825285,77626-Jul- 201213:01x64
For all supported IA-64-based versions of Windows Server 2008 R2 SP1
File nameFile versionFile sizeDateTimePlatform
Wfservicesreg.exe3.5.594.5825472,65626-Jul-201212:54IA- 64
Note Because of file dependencies, the most recent fix that contains these files may also contain additional files.


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


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