Backup application that calls the VSS service becomes unresponsive when the DFSR service is running in Windows

Consider the following scenario:
  • You use a backup application that calls the Volume Shadow Copy Service (VSS) on a computer that's running Windows 8.1 or Windows Server 2012 R2.
  • The Distributed File System Replication (DFSR) service is running on the computer.

In this scenario, the backup process becomes unresponsive.
This problem occurs because of a race condition in the DFSR service as it may incorrectly lock a file causing the backup application to become unresponsive.

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 update in Windows 8.1 or Windows Server 2012 R2, you must first have update 2919355 installed.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any previously released hotfix.

File information

The English (United States) version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.

Windows 8.1 and Windows Server 2012 R2 file information and notes

Important Windows 8.1 and Windows Server 2012 R2 hotfixes are included in the same packages. However, only "Windows 8.1" is listed on the Hotfix Request page. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows 8.1" 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 0.17 xxxWindows 8.1 and Windows 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 for Windows 8.1 and Windows Server 2012 R2" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are extremely 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.
For all supported x64-based versions of Windows 8.1 and Windows Server 2012 R2
File nameFile versionFile sizeDateTimePlatform
Dfsrprovs.mofNot applicable75,76122-Aug-201306:48Not applicable
Dfsrwmiv2.mofNot applicable40,48418-Jul-201315:53Not applicable
Dfsrwmiv2_uninstall.mofNot applicable2,70818-Jun-201315:17Not applicable

Additional file information for Windows 8.1 and for Windows Server 2012 R2

Additional files for all supported x64-based versions of Windows 8.1 and Windows Server 2012 R2
File propertyValue
File nameAmd64_577d6194225972e8f2d35d87cbad0cb6_31bf3856ad364e35_6.3.9600.17795_none_2140241018aa0925.manifest
File versionNot applicable
File size712
Date (UTC)13-Apr-2015
Time (UTC)19:02
PlatformNot applicable
File nameAmd64_microsoft-windows-dfsr-core-serveronly_31bf3856ad364e35_6.3.9600.17795_none_8e40322f7bc5986e.manifest
File versionNot applicable
File size41,007
Date (UTC)13-Apr-2015
Time (UTC)19:02
PlatformNot applicable
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.

Article ID: 3054249 - Last Review: 06/26/2015 02:25:00 - Revision: 2.0

Windows Server 2012 R2 Datacenter, Windows Server 2012 R2 Essentials, Windows Server 2012 R2 Foundation, Windows Server 2012 R2 Standard, Windows 8.1, Windows 8.1 Enterprise, Windows 8.1 Pro

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