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Installing the .NET Framework 3.5 on Windows 8 or 8.1

.NET Framework 4.5

The .NET Framework is an integral part of many applications running on Windows and provides common functionality for those applications to run. For developers, the .NET Framework provides a consistent programming model for building applications. if you are using the Windows operating system, the .NET Framework may already be installed on your computer. Specifically, the .NET Framework 4.5 is included with Windows 8 and installed on your computer with the Windows 8 operating system. Similarly, the .NET Framework 4.5.1 is included with Windows 8.1. In other cases, you may need to enable the .NET Framework so that apps built against it can run.

Important note Important

There is no download for the .NET Framework 3.5 for Windows 8 or Windows 8.1. You must enable the .NET Framework 3.5 in Control Panel by following the instructions provided in this article.

For example, the .NET Framework 3.5 is not automatically installed with Windows 8 or Windows 8.1. To run apps that require the .NET Framework 3.5 on Windows 8 or later, you must enable version 3.5 on your computer. There are two ways you can do this: by installing or running an app that requires the .NET Framework 3.5 (that is, by installing the .NET Framework 3.5 on demand), or by enabling the .NET Framework 3.5 in Control Panel. Both options require an Internet connection.

In general, you should not uninstall any versions of the .NET Framework from your computer, because an app you use may depend on a specific version and may break if that version is removed. Multiple versions of the .NET Framework can be loaded on a single computer at the same time. This means that you do not have to uninstall previous versions in order to install a later version.

Important notes:

  • Use the .NET Framework 3.5 for apps built for versions 2.0 and 3.0 as well as 3.5.

  • Installing a Windows language pack before installing the .NET Framework 3.5 will cause the .NET Framework 3.5 installation to fail. Install the .NET Framework 3.5 before installing any Windows language packs.

  • Windows CardSpace is not available with the .NET Framework 3.5 on Windows 8.

If an app requires the .NET Framework 3.5, but doesn't find that version enabled on your computer, it displays the following message box, either during installation, or when you run the app for the first time. In the message box, choose Install this feature to enable the .NET Framework 3.5. This option requires an Internet connection.

Prompt for installing the .NET Framework 3.5 on demand

Dialog box for 3.5 install on Windows 8

You can enable the .NET Framework 3.5 yourself through Control Panel. This option requires an Internet connection.

To enable the .NET Framework 3.5 in Control Panel

  1. On the Start screen, type and then choose Control Panel. (To access the Start screen, press the Windows logo key on your keyboard.)

  2. Choose Programs, and then choose Turn Windows features on or off.

  3. Select the .NET Framework 3.5 (includes .NET 2.0 and 3.0) check box.

You do not need to select the child items for Windows Communication Foundation (WCF) HTTP activation unless you are a developer who requires WCF script and handler mapping functionality.

Turning Windows features on or off in Control Panel

Turn Windows Features On Off

If installing the .NET Framework 3.5 on demand or enabling it in Control Panel fails, you may get one of the following error messages:

  • 0x800f0906: “Windows couldn't connect to the Internet to download necessary files. Make sure that you're connected to the Internet, and click Retry to try again.”

  • 0x800F081F: “The changes could not be completed. Please reboot your computer and try again.”

These messages may be displayed for the following reasons:

  • Your computer is not connected to the Internet. Please connect, and then retry the operation.

    If you cannot connect to the Internet, you can enable the .NET Framework 3.5 by using the Deployment Image Servicing and Management (DISM) command-line tool and specifying the installation media (ISO image or DVD) you installed Windows 8 from.

    1. In Windows 8 or Windows Server 2012, open a Command Prompt window with administrative credentials (that is, choose Run as administrator).

    2. To install the .NET Framework 3.5 from installation media located in the D:\sources\sxs directory, use the following command:

      DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /LimitAccess /Source:d:\sources\sxs


      • /Online targets the operating system you're running (instead of an offline Windows image).

      • /Enable-Feature /FeatureName:NetFx3 specifies that you want to enable the .NET Framework 3.5.

      • /All enables all parent features of the .NET Framework 3.5.

      • /LimitAccess prevents DISM from contacting Windows Update.

      • /Source specifies the location of the files needed to restore the feature (in this example, the D:\sources\sxs directory).

      For more information about DISM parameters and options, see How to Enable or Disable Windows Features

  • You are using a local source, but the network location is inaccessible or doesn’t have the right content. Install the .NET Framework 3.5 from installation media as described in the previous bullet point.

  • Your administrator has configured your computer to use Windows Server Update Services (WSUS) instead of Windows Update for servicing. Ask your administrator to enable the policy to use Windows Update instead of WSUS.

If these instructions do not correct the problem, download the paper Microsoft .NET Framework 3.5 Deployment Considerations from the Windows Dev Center for more extensive troubleshooting information.

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