Files aren't fully optimized and a deduplication cache lock contention issue occurs in Windows Server 2012 R2

This article describes some issues that occur if you enable the data deduplication feature in Windows Server 2012. A hotfix is available to fix these issues. The hotfix has a prerequisite and a restart requirement.
Assume that you have a computer that's running Windows Server 2012 R2 and you have enabled data deduplication on one or more volumes on the system. In this situation, you may encounter one of the following issues.

Issue 1

When you run optimization jobs on files, files aren't fully optimized when deduplication frequently stops the optimization of large files.

Issue 2

A deduplication cache lock contention issue causes system performance degradation when the deduplication cache is thrashed.
Issue 1

This issue occurs because the optimization is tracked incorrectly with a soon-to-be-deleted old stream handle. The optimization is stopped when the old handle is cleaned up.

Issue 2

This issue is a result of the lock contention issue in deduplication chunk cache that's exposed by cache thrashing.
Hotfix information
Important If you install a language pack after you install this hotfix, you must reinstall this hotfix. Therefore, we recommend that you install any language packs that you need before you install this hotfix. For more information, see Add language packs to Windows.

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that's described in this article. Apply this hotfix only to systems that are experiencing this specific problem.

If the hotfix is available for download, there's a "Hotfix Download Available" section at the top of this Knowledge Base article. If this section doesn't appear, submit a request to Microsoft Customer Service and Support to get 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 don't qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft website: Note The "Hotfix Download Available" form displays the languages for which the hotfix is available. If you don't see your language, it's because a hotfix isn't available for that language.


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

Registry information

To use the hotfix in this package, you don't have to make any changes to the registry.

Restart requirement

You have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix doesn't replace a previously released hotfix.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
See 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. The dates and times for these files are listed in Coordinated Universal Time (UTC). Be aware that dates and times for these files on your local computer are displayed in your local time and with your current daylight saving time bias. The dates and times may also change when you perform certain operations on the files.

Windows Server 2012 R2

Important Windows 8.1 hotfixes and Windows Server 2012 R2 hotfixes are included in the same packages. However, hotfixes on the Hotfix Request page are listed under both operating systems. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows 8.1/Windows Server 2012 R2" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each hotfix applies to.

  • 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 0.18 xxxWindows Server 2012 R2RTMGDR
  • The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately 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 aren't 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_2e3338398ede05105212a0c6bf2d83e3_31bf3856ad364e35_6.3.9600.18050_none_7a0c0881439a459a.manifest
File versionNot applicable
File size704
Date (UTC)09-Sep-2015
Time (UTC)02:45
PlatformNot applicable
File nameAmd64_microsoft-windows-dedup-filter_31bf3856ad364e35_6.3.9600.18050_none_f8ec2df92b9a8561.manifest
File versionNot applicable
File size7,227
Date (UTC)09-Sep-2015
Time (UTC)02:45
PlatformNot applicable
File nameUpdate.mum
File versionNot applicable
File size1,583
Date (UTC)09-Sep-2015
Time (UTC)02:45
PlatformNot applicable

Article ID: 3094197 - Last Review: 11/04/2015 08:04:00 - 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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