Hyper-V hosts crash in csvfs.sys in Windows Server 2012 R2

Symptoms

Windows Server 2012 R2 Hyper-V hosts may crash in the csvfs.sys file process when you perform backup with certain backup applications.

Cause

This issue occurs if a backup solution sends the CsvControlQueryFileRevision request on a cleaned-up file object. In that situation, CSVFS may crash because one of its internal functions assumes that a valid file object will be passed.

How to get this update

Method 1: Windows Update

This update is available through Windows Update. For more information about 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.

Prerequisites

To install this update, you must have the 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 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.

Status

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

References

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 8.1 and Windows Server 2012 R2
Additional file information
Third-party information disclaimer

Properties

Article ID: 3216763 - Last Review: Feb 2, 2017 - Revision: 12

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

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