Sign in with Microsoft
New to Microsoft? Create an account.


This article describes the issue that is fixed in the update package for Microsoft Office Communications Server 2007 R2, Audio/Video Conferencing Server that is dated July 2010.


Issue that this update fixes

This update package fixes the following issue:

  • 2251423 You may receive a serverBusy error on Office Communications Server 2007 R2, Conference Attendant when a user is transferred to an audio conference

This cumulative update also includes the following previously released updates:

  • 981257 An update to the Office Communications Server 2007 R2 Audio Video Conferencing server is required to maintain existing behavior after update 977547 is applied

  • 972773 The diagnostics information for an audio or video conference call that failed is not available in the log of an Office Communications Server 2007 R2-based application

  • 972771 The Audio Video Multipoint Conferencing Unit (AVMCU) drops all incoming comfort noise packets when you use call users through the AVMCU server in a Communications Server 2007 R2 conference

More Information

Update package information

Download Center

The following file is available for download from the Microsoft Download Center:
Download Download the AVMCU.msp package now.

Release Date: July 2010

For more information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 How to obtain Microsoft support files from online services Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help prevent any unauthorized changes to the file.

By Contacting Microsoft Support

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 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, visit the following Microsoft Web site: 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.


There are no prerequisites for installing this update.

Restart requirement

You may have to restart the server at the end of the installation of the update.

Hotfix replacement information

This hotfix package replaces hotfix package 977934. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

977934 Description of the update package for Office Communications Server 2007 R2, Audio/Video Conferencing Server: April 2010

Registry information

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

Update package installation information

To install this update package, install the OCS2007R2-KB2028578-amd64-AVMCU.msp packages on the following computers:

  • Office Communications Server – Standard Edition

  • Office Communications Server – Enterprise Edition Consolidated

  • Office Communications Server 2007 R2 – Enterprise Edition Distributed – Audio Video Conferencing Server

Note When you apply this update on servers that run Windows 2008 and have the User Account Control (UAC) enabled, make sure that you start the installation of the update (.msp) by using the elevated Command Prompt. To do this, follow these steps:

  1. Click Start the Start button , click
    All Programs, click Accessories, and then right-click Command Prompt.

  2. Click Run as administrator.User Account Control If you are prompted for an administrator password or for confirmation, type the password, or provide confirmation.

  3. Start the update (.msp) at the command prompt.

Removal information

To remove this update package, use the Add or Remove Programs item in Control Panel.

You may be prompted for restart after you uninstall the update for Office Communications Server 2007 R2, Audio Video Conferencing Server.

Sometimes, when you try to uninstall the update package, you are prompted for the source CD. If this behavior occurs, insert the source CD or provide the path where the source files can be found.

File information

This update may not contain all the files that you must have to fully update a product to the latest build. This update contains only the files that you must have to correct the issue that is listed in this article.

After the update is installed, the global version of this update has the file attributes, or a later version of the file attributes, that are listed in the following table:

File name

File version

File size









































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 updatesFor more information about the latest updates for Communications Server 2007 R2, click the following article number to view the article in the Microsoft Knowledge Base:

968802 Updates for Communications Server 2007 R2

Need more help?

Expand your skills
Explore Training
Get new features first
Join Microsoft Insiders

Was this information helpful?

What affected your experience?

Thank you for your feedback!