This article describes an issue in which all virtual machines (VM) go into failed state on a Windows Server 2012 R2 host and may not be migrated automatically to other cluster nodes. An update is available to fix this issue. Before you install this update, see the Prerequisites section.
This issue occurs when Hyper-V cluster hosts use virtual machine queue (VMQ) capable NICs (high performance NICs) and when the VMQ feature is enabled. All VMs on the hosts would go into failed state instead of failing over to other nodes.
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 UpdateThis update is provided as a Recommended update on Windows Update. For more information on how to run Windows Update, see How to get an update through Windows Update.
Method 2: Microsoft Update CatalogTo get the stand-alone package for this update, go to the Microsoft Update Catalog website.
PrerequisitesTo install this update, you should first install April 2014, update rollup for Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2 (2919355) in Windows Server 2012 R2.
Registry informationTo apply this update, you don't have to make any changes to the registry.
Restart requirementYou may have to restart the computer after you apply this update.
Update replacement informationThis update doesn't replace a previously released update.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Article ID: 3145432 - Last Review: May 10, 2016 - Revision: 1
Windows Server 2012 R2 Datacenter, Windows Server 2012 R2 Standard, Windows Server 2012 R2 Essentials, Windows Server 2012 R2 Foundation