How to temporarily block the installation of the .NET Framework 4 Client Profile on a computer that is running Windows Vista or Windows 7

The Microsoft .NET Framework 4 is the newest version of the .NET Framework. The .NET Framework is a comprehensive and consistent programming model for building applications that have visually stunning user experiences, seamless and secure communication, and the ability to model a range of business processes.

For more information about Microsoft .NET Framework, click the following article number to view the article in the Microsoft Knowledge Base:

829019 Benefits of the Microsoft .NET Framework

The Microsoft .NET Framework 4 will be released on Windows Update (WU). Additionally, it will be offered in Windows Server Update Service (WSUS). Specifically, the .NET Framework 4 Client Profile will be released as a recommended update on a computer that is running Windows Vista and on a computer that is running Windows 7. A recommended update will be automatically installed, depending on the Automatic Update settings of a particular computer. The Client Profile will also be released as an optional update for Windows XP. With Windows XP, you must manually run Windows Update and select the .NET Framework 4 Client Profile. Computers that are running Windows Server 2003, Windows Server 2008, or Windows Server 2008 R2 will be offered the .NET Framework 4 as an optional update.

Important We recommend that you do not block the installation of the .NET Framework 4. However, if you have a compelling business reason to do this temporarily in environments where the Automatic Updates feature is enabled, you can modify the registry to temporarily block the installation of the .NET Framework 4 Client Profile.

Note Organizations do not have to modify the registry in environments that are managed by using an update management solution such as Microsoft Windows Server Update Services (WSUS) or Systems Management Server (SMS) 2003. Organizations can use these products to fully manage the deployment of updates that are released through Windows Update and through Microsoft Update.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs.

For more information about how to back up and restore the registry, visit the Microsoft Web site that is appropriate for your operating system.

Windows 7Windows VistaTo temporarily block the installation of the .NET Framework 4 Client Profile in an environment in which the Automatic Updates feature is enabled on a computer that is running Windows Vista or on a computer that is running Windows 7, follow these steps.

Note After you use this method to temporarily block the installation of the .NET Framework 4, we recommend that you do not leave these changes in force for any length of time because of customer needs. These needs include security, stability, and servicing.

1. Back up the registry.
2. Start Registry Editor. To do this, click Start, click Run, type regedit, and then click OK.
3. Locate and then click to select the following registry subkey:
   
   HKEY_LOCAL_MACHINE\Software\Microsoft\NET Framework Setup\NDP
4. After you select the subkey that is specified in step 3, point to New on the Edit menu, and then click Key.
5. Type WU, and then press ENTER.
6. Right-click WU, point to New, and then click DWORD Value.
7. Type BlockNetFramework4, and then press ENTER.
8. Right-click BlockNetFramework4, and then click Modify.
9. In the Value data box, type 1, and then click OK.
10. On the File menu, click Exit to exit Registry Editor.

Note When this registry key is present, Windows Update will not offer the .NET Framework 4. You do not have to hide this update. Additionally, there will be no warning or error messages.