An application that uses the Remote Desktop Connection ActiveX control to provide virtualized sessions crashes in Windows Server 2008 R2 or in Windows 7

Symptoms

Consider the following scenario:

  • You have a computer that is running Windows Server 2008 R2 or Windows 7.

  • You run an application that uses the Remote Desktop Connection ActiveX control (Mstscax.dll) to provide virtualized sessions.

  • Multiple user accounts are running applications in the virtualized sessions provided by the application.

In this scenario, the application crashes, and all virtualized sessions are disconnected.

Note This issue also occurs in Windows MultiPoint Server 2010. The SRCShell.exe in Windows MultiPoint Server 2010 uses Mstscax.dll to provide virtualized sessions. After this issue occurs, the SRCShell.exe crashes.

Cause

This issue occurs because an access violation exception occurs in the application that provides virtualized sessions when uninitialized variables are accessed. The uninitialized variables occur because the Desktop Windows Manager (DWM) is disabled on the remote desktop server when an application on the server opens a virtual channel to the DWM proxy on the client.

Note The Remote Desktop Protocol (RDP) enables virtual channels between a server and a client to transfer specific information. The clipboard, the remote audio, and the DWM all use this mechanism to relay information on the server to their proxies that are located on the client.

Resolution

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 website:

http://support.microsoft.com/contactus/?ws=supportNote 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 be running one of the following operating systems:

  • Windows 7

  • Windows 7 Service Pack 1 (SP1)

  • Windows Server 2008 R2

  • Windows Server 2008 R2 Service Pack 1 (SP1)

Registry information

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

Restart requirement

You do not have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The global 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 7 and Windows Server 2008 R2 file information notes


Important Windows 7 hotfixes and Windows Server 2008 R2 hotfixes are included in the same packages. However, hotfixes on the Hotfix Request page are listed under both operating systems. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows 7/Windows Server 2008 R2" 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.

    Version

    Product

    SR_Level

    Service branch

    6.1.760
    0.20xxx

    Windows 7 and Windows Server 2008 R2

    RTM

    LDR

    6.1.760
    1.17xxx

    Windows 7 and Windows Server 2008 R2

    SP1

    GDR

    6.1.760
    1.21xxx

    Windows 7 and Windows Server 2008 R2

    SP1

    LDR

  • GDR service branches contain only those fixes that are widely released to address widespread, very important issues. LDR service branches contain hotfixes in addition to widely released fixes.

  • 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 R2 and for Windows 7" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are extremely important to maintain the state of the updated components. 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 7

File name

File version

File size

Date

Time

Platform

Mstsc.exe

6.1.7600.20861

1,034,752

18-Dec-2010

05:25

x86

Mstsc.mof

Not applicable

1,199

22-Jul-2009

23:03

Not applicable

Mstsc.exe

6.1.7601.21624

1,049,600

18-Dec-2010

07:56

x86

Mstsc.mof

Not applicable

1,199

12-Nov-2010

23:41

Not applicable

Aaclient.dll

6.1.7600.20861

131,584

18-Dec-2010

05:25

x86

Aaclient.mof

Not applicable

1,261

22-Jul-2009

22:58

Not applicable

Mstscax.dll

6.1.7600.20861

2,705,408

18-Dec-2010

05:29

x86

Mstscax.mof

Not applicable

2,054

22-Jul-2009

23:02

Not applicable

Tsgqec.dll

6.1.7600.20861

36,864

18-Dec-2010

05:30

x86

Aaclient.dll

6.1.7601.17514

131,584

20-Nov-2010

12:18

x86

Aaclient.mof

Not applicable

1,261

10-Jun-2009

21:14

Not applicable

Mstscax.dll

6.1.7601.21624

3,215,872

18-Dec-2010

07:57

x86

Mstscax.mof

Not applicable

2,054

10-Jun-2009

21:17

Not applicable

Tsgqec.dll

6.1.7601.17514

36,864

20-Nov-2010

12:21

x86

For all supported x64-based versions of Windows 7 and of Windows Server 2008 R2

File name

File version

File size

Date

Time

Platform

Mstsc.exe

6.1.7600.20861

1,098,752

18-Dec-2010

06:04

x64

Mstsc.mof

Not applicable

1,199

22-Jul-2009

23:22

Not applicable

Mstsc.exe

6.1.7601.21624

1,116,672

18-Dec-2010

08:50

x64

Mstsc.mof

Not applicable

1,199

12-Nov-2010

23:42

Not applicable

Aaclient.dll

6.1.7600.20861

158,720

18-Dec-2010

06:04

x64

Aaclient.mof

Not applicable

1,261

22-Jul-2009

23:18

Not applicable

Mstscax.dll

6.1.7600.20861

3,155,968

18-Dec-2010

06:08

x64

Mstscax.mof

Not applicable

2,054

22-Jul-2009

23:20

Not applicable

Tsgqec.dll

6.1.7600.20861

44,032

18-Dec-2010

06:09

x64

Aaclient.dll

6.1.7601.17514

158,720

20-Nov-2010

13:25

x64

Aaclient.mof

Not applicable

1,261

10-Jun-2009

20:31

Not applicable

Mstscax.dll

6.1.7601.21624

3,715,584

18-Dec-2010

08:51

x64

Mstscax.mof

Not applicable

2,054

10-Jun-2009

20:34

Not applicable

Tsgqec.dll

6.1.7601.17514

44,032

20-Nov-2010

13:27

x64

Mstsc.exe

6.1.7600.20861

1,034,752

18-Dec-2010

05:25

x86

Mstsc.mof

Not applicable

1,199

22-Jul-2009

23:03

Not applicable

Mstsc.exe

6.1.7601.21624

1,049,600

18-Dec-2010

07:56

x86

Mstsc.mof

Not applicable

1,199

12-Nov-2010

23:41

Not applicable

Aaclient.dll

6.1.7600.20861

131,584

18-Dec-2010

05:25

x86

Aaclient.mof

Not applicable

1,261

22-Jul-2009

22:58

Not applicable

Mstscax.dll

6.1.7600.20861

2,705,408

18-Dec-2010

05:29

x86

Mstscax.mof

Not applicable

2,054

22-Jul-2009

23:02

Not applicable

Tsgqec.dll

6.1.7600.20861

36,864

18-Dec-2010

05:30

x86

Aaclient.dll

6.1.7601.17514

131,584

20-Nov-2010

12:18

x86

Aaclient.mof

Not applicable

1,261

10-Jun-2009

21:14

Not applicable

Mstscax.dll

6.1.7601.21624

3,215,872

18-Dec-2010

07:57

x86

Mstscax.mof

Not applicable

2,054

10-Jun-2009

21:17

Not applicable

Tsgqec.dll

6.1.7601.17514

36,864

20-Nov-2010

12:21

x86

For all supported IA-64-based versions of Windows Server 2008 R2

File name

File version

File size

Date

Time

Platform

Mstsc.exe

6.1.7600.20861

1,661,952

18-Dec-2010

05:13

IA-64

Mstsc.mof

Not applicable

1,199

22-Jul-2009

23:47

Not applicable

Mstsc.exe

6.1.7601.21624

1,696,256

18-Dec-2010

09:34

IA-64

Mstsc.mof

Not applicable

1,199

12-Nov-2010

23:42

Not applicable

Aaclient.dll

6.1.7600.20861

339,968

18-Dec-2010

05:13

IA-64

Aaclient.mof

Not applicable

1,261

22-Jul-2009

23:44

Not applicable

Mstscax.dll

6.1.7600.20861

6,091,776

18-Dec-2010

05:17

IA-64

Mstscax.mof

Not applicable

2,054

22-Jul-2009

23:46

Not applicable

Tsgqec.dll

6.1.7600.20861

97,792

18-Dec-2010

05:19

IA-64

Aaclient.dll

6.1.7601.21624

339,968

18-Dec-2010

09:35

IA-64

Aaclient.mof

Not applicable

1,261

10-Jun-2009

20:36

Not applicable

Mstscax.dll

6.1.7601.21624

6,301,696

18-Dec-2010

09:35

IA-64

Mstscax.mof

Not applicable

2,054

10-Jun-2009

20:38

Not applicable

Tsgqec.dll

6.1.7601.17514

97,792

20-Nov-2010

10:28

IA-64

Mstsc.exe

6.1.7600.20861

1,034,752

18-Dec-2010

05:25

x86

Mstsc.mof

Not applicable

1,199

22-Jul-2009

23:03

Not applicable

Mstsc.exe

6.1.7601.21624

1,049,600

18-Dec-2010

07:56

x86

Mstsc.mof

Not applicable

1,199

12-Nov-2010

23:41

Not applicable

Aaclient.dll

6.1.7600.20861

131,584

18-Dec-2010

05:25

x86

Aaclient.mof

Not applicable

1,261

22-Jul-2009

22:58

Not applicable

Mstscax.dll

6.1.7600.20861

2,705,408

18-Dec-2010

05:29

x86

Mstscax.mof

Not applicable

2,054

22-Jul-2009

23:02

Not applicable

Tsgqec.dll

6.1.7600.20861

36,864

18-Dec-2010

05:30

x86

Aaclient.dll

6.1.7601.17514

131,584

20-Nov-2010

12:18

x86

Aaclient.mof

Not applicable

1,261

10-Jun-2009

21:14

Not applicable

Mstscax.dll

6.1.7601.21624

3,215,872

18-Dec-2010

07:57

x86

Mstscax.mof

Not applicable

2,054

10-Jun-2009

21:17

Not applicable

Tsgqec.dll

6.1.7601.17514

36,864

20-Nov-2010

12:21

x86

Workaround

Workaround for Windows 7 and for Windows Server 2008 R2

To work around the issue, start the DWM service on the computer.

Note This method causes drawback on the processing power on the computer and requires more bandwidth.

Status

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

More Information

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 updates

For more information about Windows MultiPoint Server 2010, visit the following Microsoft webpage:

Introduction to Windows MultiPoint Server 2010This issue may occur when an application runs in a Remote Desktop Services session by executing the following call.

WTSVirtualChannelOpenEx(
WTS_CURRENT_SESSION,
"dwmprox",
WTS_CHANNEL_OPTION_DYNAMIC);

Additional file information

Additional file information for Windows 7 and for Windows Server 2008 R2

Additional files for all supported x86-based versions of Windows 7

File name

X86_38c1b79260f0810e24b5f0dbc9074645_31bf3856ad364e35_6.1.7600.20861_none_529f73a7f1cbc162.manifest

File version

Not applicable

File size

1,093

Date (UTC)

21-Dec-2010

Time (UTC)

00:25

Platform

Not applicable

File name

X86_fed5f1aec1f9e351fd4d9d556bcce782_31bf3856ad364e35_6.1.7601.21624_none_f5202520aa984226.manifest

File version

Not applicable

File size

1,093

Date (UTC)

21-Dec-2010

Time (UTC)

00:25

Platform

Not applicable

File name

X86_microsoft-windows-t..minalservicesclient_31bf3856ad364e35_6.1.7600.20861_none_4e4de6cb9b7c1c97.manifest

File version

Not applicable

File size

20,880

Date (UTC)

18-Dec-2010

Time (UTC)

05:59

Platform

Not applicable

File name

X86_microsoft-windows-t..minalservicesclient_31bf3856ad364e35_6.1.7601.21624_none_5062845f987f64c4.manifest

File version

Not applicable

File size

20,880

Date (UTC)

18-Dec-2010

Time (UTC)

08:33

Platform

Not applicable

File name

X86_microsoft-windows-t..s-clientactivexcore_31bf3856ad364e35_6.1.7600.20861_none_305fa0f3400cc316.manifest

File version

Not applicable

File size

131,498

Date (UTC)

18-Dec-2010

Time (UTC)

06:00

Platform

Not applicable

File name

X86_microsoft-windows-t..s-clientactivexcore_31bf3856ad364e35_6.1.7601.21624_none_32743e873d100b43.manifest

File version

Not applicable

File size

140,967

Date (UTC)

21-Dec-2010

Time (UTC)

00:27

Platform

Not applicable

Additional files for all supported x64-based versions of Windows 7 and of Windows Server 2008 R2

File name

Amd64_4a02d8c886c9a5383f88affa3c268863_31bf3856ad364e35_6.1.7600.20861_none_e82ba6834b2a5de7.manifest

File version

Not applicable

File size

1,838

Date (UTC)

21-Dec-2010

Time (UTC)

00:25

Platform

Not applicable

File name

Amd64_8564218264cec6a742a4572f59fd71ef_31bf3856ad364e35_6.1.7601.21624_none_6b19cd11806929dc.manifest

File version

Not applicable

File size

1,838

Date (UTC)

21-Dec-2010

Time (UTC)

00:25

Platform

Not applicable

File name

Amd64_microsoft-windows-t..minalservicesclient_31bf3856ad364e35_6.1.7600.20861_none_aa6c824f53d98dcd.manifest

File version

Not applicable

File size

20,886

Date (UTC)

18-Dec-2010

Time (UTC)

06:54

Platform

Not applicable

File name

Amd64_microsoft-windows-t..minalservicesclient_31bf3856ad364e35_6.1.7601.21624_none_ac811fe350dcd5fa.manifest

File version

Not applicable

File size

20,886

Date (UTC)

18-Dec-2010

Time (UTC)

09:27

Platform

Not applicable

File name

Amd64_microsoft-windows-t..s-clientactivexcore_31bf3856ad364e35_6.1.7600.20861_none_8c7e3c76f86a344c.manifest

File version

Not applicable

File size

131,504

Date (UTC)

18-Dec-2010

Time (UTC)

06:56

Platform

Not applicable

File name

Amd64_microsoft-windows-t..s-clientactivexcore_31bf3856ad364e35_6.1.7601.21624_none_8e92da0af56d7c79.manifest

File version

Not applicable

File size

140,973

Date (UTC)

21-Dec-2010

Time (UTC)

00:29

Platform

Not applicable

File name

Wow64_microsoft-windows-t..minalservicesclient_31bf3856ad364e35_6.1.7600.20861_none_b4c12ca1883a4fc8.manifest

File version

Not applicable

File size

13,023

Date (UTC)

18-Dec-2010

Time (UTC)

05:51

Platform

Not applicable

File name

Wow64_microsoft-windows-t..minalservicesclient_31bf3856ad364e35_6.1.7601.21624_none_b6d5ca35853d97f5.manifest

File version

Not applicable

File size

13,023

Date (UTC)

18-Dec-2010

Time (UTC)

08:24

Platform

Not applicable

File name

X86_microsoft-windows-t..s-clientactivexcore_31bf3856ad364e35_6.1.7600.20861_none_305fa0f3400cc316.manifest

File version

Not applicable

File size

131,498

Date (UTC)

18-Dec-2010

Time (UTC)

06:00

Platform

Not applicable

File name

X86_microsoft-windows-t..s-clientactivexcore_31bf3856ad364e35_6.1.7601.21624_none_32743e873d100b43.manifest

File version

Not applicable

File size

140,967

Date (UTC)

21-Dec-2010

Time (UTC)

00:29

Platform

Not applicable

Additional files for all supported IA-64-based versions of Windows Server 2008 R2

File name

Ia64_50c1bac89f43ad634570a46a1689368a_31bf3856ad364e35_6.1.7601.21624_none_dc82a71e6603f95e.manifest

File version

Not applicable

File size

1,835

Date (UTC)

21-Dec-2010

Time (UTC)

00:25

Platform

Not applicable

File name

Ia64_cf1e802747784a5b4c58b71cb7ee9e02_31bf3856ad364e35_6.1.7600.20861_none_5286baa16736741a.manifest

File version

Not applicable

File size

1,835

Date (UTC)

21-Dec-2010

Time (UTC)

00:25

Platform

Not applicable

File name

Ia64_microsoft-windows-t..minalservicesclient_31bf3856ad364e35_6.1.7600.20861_none_4e4f8ac19b7a2593.manifest

File version

Not applicable

File size

20,883

Date (UTC)

18-Dec-2010

Time (UTC)

06:53

Platform

Not applicable

File name

Ia64_microsoft-windows-t..minalservicesclient_31bf3856ad364e35_6.1.7601.21624_none_50642855987d6dc0.manifest

File version

Not applicable

File size

20,883

Date (UTC)

18-Dec-2010

Time (UTC)

09:59

Platform

Not applicable

File name

Ia64_microsoft-windows-t..s-clientactivexcore_31bf3856ad364e35_6.1.7600.20861_none_306144e9400acc12.manifest

File version

Not applicable

File size

131,501

Date (UTC)

18-Dec-2010

Time (UTC)

06:53

Platform

Not applicable

File name

Ia64_microsoft-windows-t..s-clientactivexcore_31bf3856ad364e35_6.1.7601.21624_none_3275e27d3d0e143f.manifest

File version

Not applicable

File size

140,970

Date (UTC)

21-Dec-2010

Time (UTC)

00:25

Platform

Not applicable

File name

Wow64_microsoft-windows-t..minalservicesclient_31bf3856ad364e35_6.1.7600.20861_none_b4c12ca1883a4fc8.manifest

File version

Not applicable

File size

13,023

Date (UTC)

18-Dec-2010

Time (UTC)

05:51

Platform

Not applicable

File name

Wow64_microsoft-windows-t..minalservicesclient_31bf3856ad364e35_6.1.7601.21624_none_b6d5ca35853d97f5.manifest

File version

Not applicable

File size

13,023

Date (UTC)

18-Dec-2010

Time (UTC)

08:24

Platform

Not applicable

File name

X86_microsoft-windows-t..s-clientactivexcore_31bf3856ad364e35_6.1.7600.20861_none_305fa0f3400cc316.manifest

File version

Not applicable

File size

131,498

Date (UTC)

18-Dec-2010

Time (UTC)

06:00

Platform

Not applicable

File name

X86_microsoft-windows-t..s-clientactivexcore_31bf3856ad364e35_6.1.7601.21624_none_32743e873d100b43.manifest

File version

Not applicable

File size

140,967

Date (UTC)

21-Dec-2010

Time (UTC)

00:25

Platform

Not applicable

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