An application may crash after you enable top-down memory in an x64-based version of Windows 7 or of Windows Server 2008 R2

Symptoms

Consider the following scenario:

  • You have a computer that is running an x64-based version of Windows 7 or of Windows Server 2008 R2.

  • You install more than 4 gigabytes (GB) of RAM in the computer.

  • You enable top-down memory on the computer.

  • You run an application on the computer. The application uses a pointer that has an address space that is more than 32 bits long.

In this scenario, the application may crash.

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 Web site:

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 an x64-based version of Windows 7 Service Pack 1 (SP1) or of Windows Server 2008 R2 Service Pack 1 (SP1).

For more information about how to obtain a Windows 7 or Windows Server 2008 R2 service pack, click the following article number to view the article in the Microsoft Knowledge Base:

976932 Information about Service Pack 1 for Windows 7 and for Windows Server 2008 R2

Registry information

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

Restart requirement

You must 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


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

    Version

    Product

    Milestone

    Service branch

    6.1.760
    1.21xxx

    Windows 7 and Windows Server 2008 R2

    SP1

    LDR

  • 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 x64-based versions of Windows 7 and of Windows Server 2008 R2

File name

File version

File size

Date

Time

Platform

Wmvencod.dll

6.1.7601.21731

1,955,328

20-May-2011

15:32

x64

Wmvsencd.dll

6.1.7601.21731

447,488

20-May-2011

15:32

x64

Wmvxencd.dll

6.1.7601.21731

641,536

20-May-2011

15:32

x64

Wmvencod.dll

6.1.7601.21731

1,568,768

20-May-2011

15:27

x86

Wmvsencd.dll

6.1.7601.21731

358,400

20-May-2011

15:27

x86

Wmvxencd.dll

6.1.7601.21731

664,576

20-May-2011

15:27

x86

Status

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

More Information

To enable top-down memory, add the following registry entry under the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management registry subkey:

Name: AllocationPreference
Type: REG_DWORD
Value: 00100000For more information about the 4-gigabyte tuning feature, visit the following Microsoft Developer Network (MSDN) website:

General information about the 4-gigabyte tuning featureFor more information about how to optimize the memory configuration of your computer, visit the following Microsoft TechNet website:

General information about how to optimize the memory configuration of your computerFor 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

Additional file information

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

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

File name

Amd64_37ea6dc60e70042d8281aeba6e6de790_31bf3856ad364e35_6.1.7601.21731_none_580d9ddcc1867847.manifest

File version

Not applicable

File size

1,040

Date (UTC)

20-May-2011

Time (UTC)

23:39

Platform

Not applicable

File name

Amd64_3b045ed2c1d42fdc8528360afdaf8861_31bf3856ad364e35_6.1.7601.21731_none_1024dada69b531bb.manifest

File version

Not applicable

File size

1,040

Date (UTC)

20-May-2011

Time (UTC)

23:39

Platform

Not applicable

File name

Amd64_780b611cb56e0294ac18ab9b970a7fce_31bf3856ad364e35_6.1.7601.21731_none_ee37c33b048ee122.manifest

File version

Not applicable

File size

1,040

Date (UTC)

20-May-2011

Time (UTC)

23:39

Platform

Not applicable

File name

Amd64_microsoft-windows-wmvencod_31bf3856ad364e35_6.1.7601.21731_none_4e955f4a2e07f9da.manifest

File version

Not applicable

File size

7,968

Date (UTC)

20-May-2011

Time (UTC)

20:36

Platform

Not applicable

File name

Amd64_microsoft-windows-wmvsencd_31bf3856ad364e35_6.1.7601.21731_none_c510b149d49b3db4.manifest

File version

Not applicable

File size

4,640

Date (UTC)

20-May-2011

Time (UTC)

20:33

Platform

Not applicable

File name

Amd64_microsoft-windows-wmvxencd_31bf3856ad364e35_6.1.7601.21731_none_a826da0e6a4a9f3f.manifest

File version

Not applicable

File size

7,326

Date (UTC)

20-May-2011

Time (UTC)

20:38

Platform

Not applicable

File name

Update.mum

File version

Not applicable

File size

1,641

Date (UTC)

20-May-2011

Time (UTC)

23:39

Platform

Not applicable

File name

X86_microsoft-windows-wmvencod_31bf3856ad364e35_6.1.7601.21731_none_f276c3c675aa88a4.manifest

File version

Not applicable

File size

7,966

Date (UTC)

20-May-2011

Time (UTC)

15:53

Platform

Not applicable

File name

X86_microsoft-windows-wmvsencd_31bf3856ad364e35_6.1.7601.21731_none_68f215c61c3dcc7e.manifest

File version

Not applicable

File size

4,638

Date (UTC)

20-May-2011

Time (UTC)

15:50

Platform

Not applicable

File name

X86_microsoft-windows-wmvxencd_31bf3856ad364e35_6.1.7601.21731_none_4c083e8ab1ed2e09.manifest

File version

Not applicable

File size

7,324

Date (UTC)

20-May-2011

Time (UTC)

15:55

Platform

Not applicable

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