Symptoms

After you install security update 2966827 or 2966828 (described in Microsoft Security Bulletin MS14-046) for the Microsoft .NET Framework 3.5, and then you try to enable the optional Microsoft .NET Framework 3.5 feature in Windows Features for the first time, the feature does not install. You may notice this failure if you "stage" the installation before you add the Microsoft .NET Framework 3.5 feature. 

When this problem occurs, you may receive an error message that resembles one of the following.

Error code

Error messages

0x800F0906

The source files could not be downloaded.
Use the "source" option to specify the location of the files that are required to restore the feature. For more information about specifying a source location, see http://go.microsoft.com/fwlink/?LinkId=243077.
The DISM log file can be found at C:\Windows\Logs\DISM\dism.log
Windows couldn't complete the requested changes.

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.

Installation of one or more roles, role services, or features failed.
The source files could not be found. Try installing the roles, role services, or features again in a new Add Roles and Features Wizard session, and on the Confirmation page of the wizard, click "Specify an alternate source path" to specify a valid location of the source files that are required for the installation. The location must be accessible by the computer account of the destination server.
0x800F0906 - CBS_E_DOWNLOAD_FAILURE

0x800F081F

The source files could not be found.
Use the "Source" option to specify the location of the files that are required to restore the feature. For more information about specifying a source location, see http://go.microsoft.com/fwlink/?LinkId=243077.
The DISM log file can be found at C:\Windows\Logs\DISM\dism.log
0x800F081F - CBS_E_SOURCE_MISSING
Error code: 0x800F081F
Error: 0x800F081F

Cause

This problem occurs because security updates 2966827 and 2966828 for Microsoft Security Bulletin MS14-046 for the .NET Framework 3.5 require metadata that is added to the system only if the Microsoft .NET Framework 3.5 feature is enabled on the system.

Status

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. The issue is now resolved by update 3005628. The workaround that is provided in the next section still unblocks customers, depending on their situation.

Workaround

To resolve the issue, install update 3005628. To work around this issue, use one of the following workarounds, as appropriate for your situation:

More Information

The information in this article applies to:

  • The Microsoft .NET Framework 3.5

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