Performance improvement for WinHTTP when lots of HTTP requests are received in Windows

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

This article describes a hotfix that improves the performance of WinHTTP in Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2. Before you apply this hotfix, notice that this hotfix has a prerequisite.

About this hotfix


This hotfix fixes a rare deadlock between WinHTTP and LSASS. This deadlock happens when WinHTTP handles lots of concurrent requests and consumes all the system threads.

Hotfix information

Important Do not install a language pack after you install this hotfix. If you do, the language-specific changes in the hotfix will not be applied, and you will have to reinstall the hotfix. For more information, see Add language packs to Windows.

A supported hotfix is available from Microsoft. 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 this specific problem.

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, submit a request to 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, visit 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.


Prerequisites

To apply this hotfix, you must have April 2014 update rollup for Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2 (2919355) installed in Windows 8.1 or Windows Server 2012 R2.

Registry information

To use the hotfix in this package, you do not have to make any changes to the registry.

Restart requirement

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

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

Status


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

References


See the terminology that Microsoft uses to describe software updates.