iSCSI target service crashes randomly in Windows Server 2012 R2

Applies to: Windows Server 2012 R2 DatacenterWindows Server 2012 R2 StandardWindows Server 2012 R2 Essentials

This article describes an issue in which the iSCSI target service crashes randomly on a Windows Server 2012 R2 server. An update is available to fix this issue. Before you install this update, see the Prerequisites section.

Note This update applies to the server products that are listed in the "Applies to" section and have the iSCSI Target Server role installed.


This issue occurs when the following conditions are true:
  • Windows Server 2012 R2-based computer that has the iSCSI Target Server role installed. 
  • The iSCSI target server encounters random I/O error.
In a rare chance iSCSI target may crash in this scenario because of a race condition in how iSCSI target finishes the failed I/O.

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 an Optional 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 Catalog

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

Update detail information


To 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 information

To apply this update, you don't have to make any changes to the registry.

Restart requirement

You may have to restart the computer after you apply this update.

Update replacement information

This 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.


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

File Information

The English (United States) version of this software update installs files that have the attributes that are listed in the following tables.