"An unrecoverable failure occurred inside the filter manager" error on a failover cluster node that hosts shared VHDx files

Applies to: Windows Server 2012 R2 DatacenterWindows Server 2012 R2 EssentialsWindows Server 2012 R2 Foundation More


When you have a failover cluster node in a Windows Server 2012 R2 environment, and this node hosts VHDx files that are configured to be shared by more than one virtual machine, you may receive a Stop error message that resembles the following:

FLTMGR_FILE_SYSTEM (f5) An unrecoverable failure occurred inside the filter manager.
This problem occurs on the node where the Cluster Shared Volume (CSV) that's hosting the VHDx file is owned. The node might be either a Scale Out File Server or Hyper-V cluster node.


This problem occurs because of a problem with the filter driver that implements the shared VHDx functionality.


To resolve this problem, apply this hotfix to all nodes of the failover cluster.

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 Server 2012 R2, you must first have update 2919355 installed.

Restart requirement

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

Hotfix replacement information

This hotfix does not replace any previously released hotfix.


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.