Consider the following scenario:

• The Group Policy Set compression algorithm for RDP data is enabled on a terminal server that is running Windows Server 2008, Windows Server 2008 R2, or Windows Server 2003. The algorithm is set to the Optimized to use less network bandwidth option or set to the Optimize to use less memory option.
  
  Note By default, these settings are set on a terminal server that is running Windows Server 2008 R2.
• A user connects to the terminal server that is running Windows Server 2008 or Windows Server 2008 R2 by using Remote Desktop Connection (RDC) client version 6.0 or 6.1. Or, a user connects to a terminal server that is running Windows Server 2003 by using RDC 6.0.6001.xxxxx on Windows XP Service Pack 3 (SP3) or by using RDC 6.1.7600.xxxxx on Windows 7.
• You connect to the same terminal server session by using Remote Desktop Connection (RDC) client version 6.0, 6.1, or 7.0. You remotely control from this terminal server session the terminal server session that was previously made. Then you end the remote control action.
  
  Note The remote control action is also known as a "Shadowing" action.

In this scenario, the terminal server session that is shadowed is incorrectly disconnected. Additionally, the user receives the following error message: When you use RDC client 7.0 to shadow a terminal server session, you can end shadowing successfully and return to your own session. When you use RDC client 6.0 or 6.1 to shadow a terminal server session, your session is disconnected together with the same error message.

When shadowing ends, the RDC client 6.0 or 6.1 clients do not reset compression or decompression context. This behavior causes the shadowed terminal server session to disconnect because the compression context is incorrectly affected.

Hotfix information

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: 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, your computer must be running one of the following Windows operating systems:

• Windows Vista Service Pack 1 (SP1)
• Windows Vista Service Pack 2 (SP2)
• Windows Server 2008
• Windows Server 2008 Service Pack 2 (SP2)

Additionally, RDP 6.0 or 6.1 must be installed.

For more information about how to obtain a Windows Vista service pack, click the following article number to view the article in the Microsoft Knowledge Base: For more information about how to obtain a Windows Server 2008 service pack, click the following article number to view the article in the Microsoft Knowledge Base:

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

Installation instructions

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

File information

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

Windows Vista and Windows Server 2008 file information notes

Important Windows Vista hotfixes and Windows Server 2008 hotfixes are included in the same packages. However, only "Windows Vista" is listed on the Hotfix Request page. To request the hotfix package that applies to one or both of these operating systems, select the hotfix that is listed under "Windows Vista" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each hotfix applies to.

• The files that apply to a specific product, SR_Level (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table.
  Collapse this tableExpand this table

  Version	Product	SR_Level	Service branch
  6.0.600 0 . 20xxx	Windows Vista	RTM	LDR
  6.0.600 1 . 22xxx	Windows Vista and Windows Server 2008	SP1	LDR
  6.0.600 2 . 22xxx	Windows Vista and Windows Server 2008	SP2	LDR

• Service Pack 1 is integrated into the release version of Windows Server 2008. Therefore, RTM milestone files apply only to Windows Vista. RTM milestone files have a 6.0.0000.xxxxxx version number.
• The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows Server 2008 and for Windows Vista" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are extremely important to maintaining the state of the updated component. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.

For all supported x86-based versions of Windows Server 2008 and of Windows Vista

For all supported x64-based versions of Windows Server 2008 and of Windows Vista

For all supported IA-64-based versions of Windows Server 2008

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

Workaround for Windows Server 2008 or for Windows Server 2008 R2

To work around this issue, disable the Set compression algorithm for RDP data policy on terminal servers.

To disable this policy on terminal servers that are running Windows Server 2008, follow these steps:

1. Open the Local Group Policy Editor, and then locate the following policy:

   Computer Configuration\Administrative Templates\Windows Component\Terminal Services\Terminal Server\Remote Session Environment\Set compression algorithm for RDP data

2. Set the value for this policy to Balances memory usage and network bandwidth.
3. Refresh the Group Policy settings to apply the settings.

To disable this policy on terminal servers that are running Windows Server 2008 R2, follow these steps:

1. Open the Local Group Policy Editor, and then locate the following policy:

   Computer Configuration\Administrative Templates\Windows Component\Remote Desktop Services\Remote Desktop Session Host\Remote Session Environment\Set compression algorithm for RDP data

2. Set the value of Set compression algorithm for RDP data to Do not use an RDP compression algorithm.
3. Refresh Group Policy settings to apply the settings.

Workaround for Windows XP Service Pack 3 or for Windows 7

To work around this issue, click to clear the Desktop Composition check box on the Experience tab in the Remote Desktop Connection dialog box of the RDC client.

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

Additional file information

Additional file information for Windows Vista and for Windows Server 2008

Additional files for all supported x86-based versions of Windows Vista and of Windows Server 2008

Additional files for all supported x64-based versions of Windows Vista and of Windows Server 2008

Additional files for all supported IA-64-based versions of Windows Server 2008