The .NET Framework 4.5.1 is distributed through Windows Update. Some customers may have a business requirement to block the automatic installation of the .NET Framework 4.5.1 in their managed environment. This article describes how to do that. This method is applicable for computers that are running one of the following operating systems:
Windows Server 2008
Windows Server 2008 R2
Windows Server 2012
Note After this method is applied on a computer, Windows Update does not provide the downloads for the .NET Framework 4.5.1 and its corresponding language packs.
The Microsoft .NET Framework 4.5.1 is being released on Windows Update and Windows Server Update Service (WSUS). The .NET Framework 4.5.1 is categorized as a recommended update on all applicable platforms. A recommended update is automatically installed depending on the Automatic Update settings of a particular computer.
We strongly recommend that you do not block the installation of the .NET Framework 4.5.1. However, if you have a business reason to temporarily block the installation in an environment in which the Automatic Updates feature is enabled, you can modify the registry to temporarily block the installation of the .NET Framework 4.5.1.
How to temporarily block the installation of the .NET Framework 4.5.1
Important Follow the steps in this section carefully. Serious problems might occur if you modify the registry incorrectly. Before you modify it, back up the registry for restoration in case problems occur.
To temporarily block the offering and installation of the .NET Framework 4.5.1 in an environment in which the Automatic Updates feature is enabled, follow these steps.
Note We recommend that you do not block the offering and installation for a long time for security, stability, and servicing reasons.
Back up the registry.
Start Registry Editor. To do this, click Start, click Run, type regedit, and then click OK.
Locate and then click to select the following registry sub key:
After you select the subkey that is specified in step 3, point to New on the Edit menu, and then click Key.
Type WU, and then press ENTER.
Right-click WU, point to New, and then click DWORD Value.
Type BlockNetFramework451, and then press ENTER.
Right-click BlockNetFramework451, and then click Modify.
In the Value data box, type 1, and then click OK.
On the File menu, click Exit to exit Registry Editor.
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 Microsoft System Center Configuration Manager. Organizations can use these products to fully manage the deployment of updates that are released through Windows Update and through Microsoft Update. Computers that can directly connect to Microsoft Update can still receive the .NET Framework 4.5.1 unless the blocker registry key that is described in this article is deployed.
For more information about these and other features of the .NET Framework 4.5.1, go to the following Microsoft website: