What should I do if Win8 has 0x800F0906 error when installing .NET 3.5?

Cause Analysis:

In Windows 8 and Windows Server 2012, .Net Framework 3.5 is an on-demand feature. Metadata based on functionality is included with Windows 8 and Windows Server 2012. However, binaries and other files associated with the feature are not included. When this feature is enabled, Windows will attempt to download the missing information to install the Windows update for that feature, and an error may occur.

Network configuration and computer installation of updates in this configuration environment can affect this process, so you may encounter errors when you first install this feature.

Solution:

This error code occurs because the computer cannot download the required files from Windows Update.

This can be caused by network, proxy or firewall configuration or by network, proxy or firewall failure.

This behavior can also be caused by a system administrator who configures the computer to use Windows Server Update Services (WSUS) instead of the Microsoft Windows Update Server. In this case, contact your system administrator and ask them to enable the optional components of the Install and Repair component to specify settings for Group Policy settings and configure alternate source file path values, or choose to download the repair content directly with Windows Update instead of the Windows server Update Service (WSUS) option.

To configure Group Policy settings, perform the following steps:

1. Start the Local Group Policy Editor or Group Policy Management Console and enter gpedit.msc-OK.

2. Expand Computer Configuration, expand Administrative Templates, and select System.

3. Open the Install and Repair component of the optional component Specify Settings Group Policy settings and then select Enable.

4. If you want to specify the source file in the Alternate File Path box, the other, specify the shared folder to contain the fully qualified path from the contents of the sourcessxs folder of the installation media. Or, specify a WIM file. To specify a WIM file as an alternate source file location, add a path prefixed with WIM: and then add an index of the image you want to use as a suffix in the WIM file. The following is an example of a value that you can specify:

a. Path to the shared folder: server_nameshareWin8sxs

b. WIM file, which 3 paths represent the index of the image in which to find the function File: WIM: server_nameshareinstall.wim:3

5. If you want to do this, select the Windows Update contact to download the repair directly instead of the Windows Server Update Services (WSUS) checkbox.

6. Click or click Ok.

7. At an elevated command prompt, type the gpupdate /force command and press Enter to apply the policy immediately:

Alternatively, you can enable the Windows installation media as the file source. The features of the .NET Framework 3.5. Follow these steps:

1. Insert the Windows 8 or Windows Server 2012 installation media.

2. At an elevated command prompt, run the following command:

Dism /Online /enable-feature /featurename:NetFx3 /All /Source:: sourcessxs /LimitAccess
< Note: In this command, there is a placeholder for the DVD drive or the drive letter of the Windows 8 installation media. For example, you can run the following command:

Dism /online /enable-feature /featurename:NetFx3/All/Source:D:sourcessxs /LimitAccess

Steps for Windows Server 2012

In Windows Server 2012, you can also specify alternate sources by using Windows PowerShell cmdlts or by using the Add Roles and Features Wizard.

To use Windows PowerShell, follow these steps:

1. Insert the Windows Server 2012 installation media.

2. In the elevated Windows PowerShell command window, run the following command:

Set WindowsFeature – NET Framework kernel name –source : sourcessxs

Note in this command In, is a placeholder for the DVD drive or the drive letter of the Windows Server 2012 installation media. For example, you can run the following command:

Install-WindowsFeature –name NET-Framework-Core –source D:sourcessxs

Using the Add Roles and Features Wizard, follow these steps :

1. Insert the Windows Server 2012 installation media.

2. Launch the Add Roles and Features Wizard.

3. On the Select Features page, select the .Net Framework 3.5 Features check box, and then click Next.

4. On the Confirm Installation Selection page, click the Specify an alternate source path link.

5. Type the path to the SxS folder on the Specify Alternate Source Path page as a local path or network share path.

6. Click OK.

7. Click Install to complete the wizard.