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

Applies to: 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: 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, 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:
    VersionProductMilestoneService branch
    6.1.760
    1.21xxx
    Windows 7 and Windows Server 2008 R2SP1LDR
  • 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 nameFile versionFile sizeDateTimePlatform
Wmvencod.dll6.1.7601.217311,955,32820-May-201115:32x64
Wmvsencd.dll6.1.7601.21731447,48820-May-201115:32x64
Wmvxencd.dll6.1.7601.21731641,53620-May-201115:32x64
Wmvencod.dll6.1.7601.217311,568,76820-May-201115:27x86
Wmvsencd.dll6.1.7601.21731358,40020-May-201115:27x86
Wmvxencd.dll6.1.7601.21731664,57620-May-201115:27x86

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: 00100000
For more information about the 4-gigabyte tuning feature, visit the following Microsoft Developer Network (MSDN) website:For more information about how to optimize the memory configuration of your computer, visit the following Microsoft TechNet website: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

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 nameAmd64_37ea6dc60e70042d8281aeba6e6de790_31bf3856ad364e35_6.1.7601.21731_none_580d9ddcc1867847.manifest
File versionNot applicable
File size1,040
Date (UTC)20-May-2011
Time (UTC)23:39
PlatformNot applicable
File nameAmd64_3b045ed2c1d42fdc8528360afdaf8861_31bf3856ad364e35_6.1.7601.21731_none_1024dada69b531bb.manifest
File versionNot applicable
File size1,040
Date (UTC)20-May-2011
Time (UTC)23:39
PlatformNot applicable
File nameAmd64_780b611cb56e0294ac18ab9b970a7fce_31bf3856ad364e35_6.1.7601.21731_none_ee37c33b048ee122.manifest
File versionNot applicable
File size1,040
Date (UTC)20-May-2011
Time (UTC)23:39
PlatformNot applicable
File nameAmd64_microsoft-windows-wmvencod_31bf3856ad364e35_6.1.7601.21731_none_4e955f4a2e07f9da.manifest
File versionNot applicable
File size7,968
Date (UTC)20-May-2011
Time (UTC)20:36
PlatformNot applicable
File nameAmd64_microsoft-windows-wmvsencd_31bf3856ad364e35_6.1.7601.21731_none_c510b149d49b3db4.manifest
File versionNot applicable
File size4,640
Date (UTC)20-May-2011
Time (UTC)20:33
PlatformNot applicable
File nameAmd64_microsoft-windows-wmvxencd_31bf3856ad364e35_6.1.7601.21731_none_a826da0e6a4a9f3f.manifest
File versionNot applicable
File size7,326
Date (UTC)20-May-2011
Time (UTC)20:38
PlatformNot applicable
File nameUpdate.mum
File versionNot applicable
File size1,641
Date (UTC)20-May-2011
Time (UTC)23:39
PlatformNot applicable
File nameX86_microsoft-windows-wmvencod_31bf3856ad364e35_6.1.7601.21731_none_f276c3c675aa88a4.manifest
File versionNot applicable
File size7,966
Date (UTC)20-May-2011
Time (UTC)15:53
PlatformNot applicable
File nameX86_microsoft-windows-wmvsencd_31bf3856ad364e35_6.1.7601.21731_none_68f215c61c3dcc7e.manifest
File versionNot applicable
File size4,638
Date (UTC)20-May-2011
Time (UTC)15:50
PlatformNot applicable
File nameX86_microsoft-windows-wmvxencd_31bf3856ad364e35_6.1.7601.21731_none_4c083e8ab1ed2e09.manifest
File versionNot applicable
File size7,324
Date (UTC)20-May-2011
Time (UTC)15:55
PlatformNot applicable