System shows a high nonpaged pool utilization from pool tag AfdP

Applies to: Windows Server 2012 R2 DatacenterWindows Server 2012 R2 StandardWindows Server 2012 R2 Essentials


Consider the following scenario:
  • You have a server that is running Windows Server 2012 R2 or Windows Server 2008 R2 Service Pack (SP1).
  • You run a third-party software package on the server.
  • The software package is a multithreaded Winsock server application.

In this scenario, the server stops responding intermittently, and the system shows a high nonpaged pool utilization from pool tag AfdP.


This problem occurs because of a nonpaged pool leak in the afd.sys driver. This leak exhausts the nonpaged pool and causes the server to stop responding.

The problem can occur if one application thread posts a Winsock Select function on a set of sockets while a second application thread is deleting one or more of the sockets.


To resolve this issue in Windows Server 2012 R2, install update 2955164. For more information about update 2955164, click the following article number to view the article in the Microsoft Knowledge Base:
2955164 Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2 update rollup: May 2014
To resolve this issue in Windows Server 2008 R2, install the hotfix that is described in this article.

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 hotfix, you must have Service Pack 1 for Windows 7 or Windows Server 2008 R2 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.


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.