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The August 2016 update rollup includes some new improvements and fixes for the Windows 8.1 and Windows Server 2012 R2 platforms. We recommend that you apply this update rollup as part of your regular maintenance routines. Before you install this update, see the Prerequisites and the Restart requirement sections.

Improvements and fixes

To learn more about the nonsecurity improvements and fixes in this update, see the "August 16, 2016 – KB3179574" section in Windows 8.1 and Windows Server 2012 R2 update history.

Known issues in this update


After you apply this update on a Remote Desktop Session (RDS) host, some new users cannot connect to an RDP session. Instead, those users see a black screen, and they are eventually disconnected. This issue occurs at unspecified intervals.

The following events are usually logged when this issue occurs:

Event Logs

Event Source






An error occurred when transitioning from CsrConnected in response to EvCsrInitialized. (ErrorCode 0x80004005)




The Windows logon process has unexpectedly terminated.


During virtual channel management, a deadlock condition occurs that prevents the RDS service from accepting new connections.


To fix this issue, install November 2016 Preview of Monthly Quality Rollup for Windows 8.1 and Windows Server 2012 R2 (KB3197875).

How to get this update

Important If you install a language pack after you install this update, you must reinstall this update. Therefore, we recommend that you install any language packs that you need before you install this update. For more information, see Add language packs to Windows.

Method 1: Windows Update

This update is provided as a Recommended update on Windows Update. For more information about how to run Windows Update, see How to get an update through Windows Update.

Method 2: Microsoft Update Catalog

To get the stand-alone package for this update, go to the Microsoft Update Catalog website.

Note You must be running Microsoft Internet Explorer 6 or a later version.

Method 3: Microsoft Download Center

The following files are available for download from the Microsoft Download Center.

Operating system


All supported x86-based versions of Windows 8.1

Download Download the package now.

All supported x64-based versions of Windows 8.1

Download Download the package now.

All supported x64-based versions of Windows Server 2012 R2

Download Download the package now.

For more information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 How to obtain Microsoft support files from online services Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help prevent any unauthorized changes to the file.

Update detail information


To apply this update, you must have April 2014 update rollup for Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2 (2919355) installed in Windows 8.1 or Windows Server 2012 R2.

Restart requirement

You must restart the computer after you apply this update.

Registry information

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

To enable the improved performance for duplicate broadcast data received in LBFO, add the follow registry subkey:

  1. In Registry Editor, locate and then select the following registry subkey:


  2. Press and hold (or right-click) <GUID>, select New, and then select DWORD (32-bit) Value.

  3. Name the new registry entry as DropStandbyReceive.

  4. Double-click the DropStandbyReceive registry entry.

  5. In the Edit DWORD Value dialog box, enter 1 in the Value data field, and then select OK.

  6. Exit Registry Editor.


  • Drop packet events are generated when there is a packet drop of the passive NIC.

  • After you set the registry subkey, you have to restart the NIC Teaming (LBFO) service by using the following commands.

    Note This causes a brief network disruption.

    sc stop mslbfoprovider
    sc start mslbfoprovider

Update replacement information

This update doesn't replace any previously released update.

File Information

File name

SHA1 hash

SHA256 hash










File informationFor a list of the files that are provided in this update, download the file list for update rollup 3179574.


For more information about Windows Update, go to the following Microsoft websites:

Troubleshoot problems with installing updates

Windows Update: Frequently Asked Questions

Learn about the terminology that Microsoft uses to describe software updates.

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