Reliability improvement update for Windows 8.1 and Windows Server 2012 R2: May 2015

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

Summary


This reliability improvement update for Windows 8.1 and Windows Server 2012 R2 fixes the following issues:
  • The Lightweight Suspend feature may cause threads that are waiting for SRWLocks, Condition Variables, or Threadpool work items to stop responding (hang).
  • The CPU usage rate control hard-caps on an idle system.

Note These issues are not obvious and are difficult to debug. This update is intended for applicable systems to apply proactively in order to increase the reliability of these systems. 

More Information


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.

Prerequisites

To apply this update in Windows 8.1 or 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.

Status


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

References


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