Network connectivity problem when Windows Server 2012 R2 is configured to use LBFO on a NIC teaming network adapter

Applies to: Windows 8.1Windows 8.1 EnterpriseWindows 8.1 Pro


You have a Windows Server 2012 R2-based computer that's configured to use Load Balancing Failover (LBFO) on a 10-gigabyte (GB) NIC teaming network adapter. However, when you restart the computer, you discover that you've lost network connectivity.


This problem occurs because of a timing issue during restart that leaves the NIC teaming network adapter in a disconnected state. Specifically, this problem occurs when the following conditions are true:
  • During miniport initialization, the multiplexer (MUX) driver registers its miniport general attributes by using a link state of Unknown.
  • The underlying miniports indicate a status of Connected.
  • The MUX driver recalculates the link state. However, it does not indicate anything because it is still in the initializing state.
  • The MUX driver changes its internal state to Paused and then recalculates its link state.
  • A diff is run between the recalculated link state and the old link state. However, because the two states are the same, no differences are indicated.


Hotfix information

A supported hotfix is available from Microsoft Support. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing the problem described in this article. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, go to the following Microsoft website: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.


To apply this hotfix, you must be running Windows 8.1 or Windows Server 2012 R2.

Additionally, you must first install update 2919355 on Windows 8.1 or Windows Server 2012 R2.

Restart requirement

You do not have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any previously released hotfix.


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.


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