The SMB Redirector may hang when the SMB protocol is used in Windows 7 SP1 or Windows 8.1

Applies to: Windows 8.1Windows 8.1 EnterpriseWindows 8.1 Pro


When the Server Message Block (SMB) protocol is used in Windows 7 Service Pack 1 (SP1) or in Windows 8.1 to access files that reside on a remote system, the SMB Redirector may hang, and the system seems to stop responding.


This problem occurs because of a deadlock condition in the SMB Redirector that occurs when the queue is full.


To resolve this problem, apply this update or hotfix to a client computer that is running Windows 7 SP1 or Windows 8.1.

Update information

The fix that resolves this problem is included in the November 2014 update rollup for Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2.

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, the client computer must meet one of the following prerequisites:

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.

More Information

The SMB Redirector component implements the client part of the file-and-print sharing functionality exposed by Windows through Microsoft Networking. The implementation is based on the Server Message Block (SMB) protocol. The SMB protocol lets the client computer to access files on another computer that implements the SMB Service part of the file-and-print sharing functionality, and access to a shared printer.


Learn about the terminology that Microsoft uses to describe software updates.