File download freezes and CPU usage high when WFP callout driver is installed in Windows 8.1 or Windows Server 2012 R2

Symptoms

Consider the following scenario:

• You install an application that uses a Windows Filtering Platform (WFP) callout driver at the stream layer on a computer.

• You download a large file (such as larger than 500 kilobytes).

In this scenario, the CPU usage is high. Therefore, the performance of the computer is slow.  

Resolution

To resolve this issue, install update rollup 2975719. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

2975719 August 2014 update rollup for Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2

Status

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

More Information

For more information about the WFP callout driver, go to the following Microsoft website:

General information about the WFP callout driver For more information about the WFP architecture, go to the following Microsoft website:

General information about the WFP architecture For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates