iSCSI target service crashes randomly in Windows Server 2012 R2

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.

Windows Server 2012 R2

  • The files that apply to a specific product, milestone (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:
    VersionProductMilestoneService branch
    6.3.960 0.17 xxxWindows Server 2012 R2RTMGDR
    6.3.960 0.18 xxxWindows Server 2012 R2RTMGDR
  • GDR service branches contain only those fixes that are widely released to address widespread, critical issues. LDR service branches contain hotfixes in addition to widely released fixes.
  • The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed in the "Additional file information" section. MUM, MANIFEST, and the associated security catalog (.cat) files, are very important to maintain the state of the updated components. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.
x64 Windows Server 2012 R2
File nameFile versionFile sizeDateTimePlatform

Additional file information

x64 Windows Server 2012 R2
File propertyValue
File nameAmd64_559cde56815a5d0300397334b1359441_31bf3856ad364e35_6.3.9600.18258_none_9118ed6be4d24cd6.manifest
File versionNot applicable
File size719
Date (UTC)03-Mar-2016
Time (UTC)23:47
PlatformNot applicable
File nameAmd64_microsoft-windows-i..get-service-service_31bf3856ad364e35_6.3.9600.18258_none_3c3e09e98e02b87a.manifest
File versionNot applicable
File size103,756
Date (UTC)03-Mar-2016
Time (UTC)19:39
PlatformNot applicable
File nameUpdate.mum
File versionNot applicable
File size1,589
Date (UTC)03-Mar-2016
Time (UTC)23:47
PlatformNot applicable

Article ID: 3146621 - Last Review: 04/20/2016 04:37:00 - Revision: 3.0

Windows Server 2012 R2 Datacenter, Windows Server 2012 R2 Standard, Windows Server 2012 R2 Essentials, Windows Server 2012 R2 Foundation

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