User connection fails when many connections are made to Windows Server 2012 R2-based RD Connection Broker

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

This article describes a hotfix for Remote Desktop Connection Broker (RD Connection Broker) in Windows Server 2012 R2. Before you install this hotfix, check out the Prerequisites section.

About this hotfix

This hotfix contains the following improvements:
  • Improves the number of successful user connections when many user connections are coming in (especially in peak logon periods).
  • Decreases CPU usage on SQL Server that's used in a High Availability-based Connection Broker deployment.
  • Optimizes the number of SQL calls that are invoked by Connection Broker when it processes RD user connections.
This hotfix improves the overall performance of the Connection Broker by being able to scale more user connections that typically occur during peak logon periods.

This hotfix applies to both RD Session Host and Virtual Desktop Infrastructure (VDI)-based deployments.

Issues fixed in this hotfix

If there's a significant high number of remote desktop connections that are made to a High-Availability RD Connection Broker in a short duration of time, you may encounter the following issues:
  • The connections experience long delays, or users are never connected to the system.
  • High CPU usage on SQL Server that's used with High Availability-based Connection Broker.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that's described in this article. Apply this hotfix only to systems that are experiencing this specific problem.

If the hotfix is available for download, there's a "Hotfix Download Available" section at the top of this Knowledge Base article. If this section doesn't appear, submit a request to Microsoft Customer Service and Support to get 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 don't 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 don't see your language, it's because a hotfix isn't available for that language.


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 Server 2012 R2.

Registry information

To use the hotfix in this package, you don't 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 doesn't replace a previously released hotfix.


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


See the terminology that Microsoft uses to describe software updates.

File Information

The English (United States) version of this software update installs files that have the attributes that are listed in the following tables. The dates and times for these files are listed in Coordinated Universal Time (UTC). Be aware that dates and times for these files on your local computer are displayed in your local time and with your current daylight saving time bias. The dates and times may also change when you perform certain operations on the files.