INTRODUCTION

By default, the maximum USB transfer size for USB storage devices is 64 kilobytes (KB). This default setting is configured in the USB port driver (Usbport.sys) in Windows 7 and Windows Server 2008 R2. An update is now available that lets you increase the maximum USB transfer size to as much as 2 megabytes (MB). See the "More Information" section for details about how to do this after you install the update.

Note For some USB storage devices, performance can be improved when you increase the maximum USB transfer size beyond the default setting of 64 KB. This update is supported when the hardware vendor provides a device information file (.inf) to set this value for USB storage devices.

Resolution

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that 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)

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


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.
    16xxx

    Windows 7 and Windows Server 2008 R2

    RTM

    GDR

    6.1.760
    0.
    21xxx

    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

  • 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

Usbstor.sys

6.1.7600.16849

75,776

15-Jul-2011

03:01

Usbstor.sys

6.1.7600.21009

75,776

15-Jul-2011

02:58

Usbstor.sys

6.1.7601.17650

76,288

15-Jul-2011

02:55

Usbstor.sys

6.1.7601.21771

76,288

15-Jul-2011

03:53

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

File name

File version

File size

Date

Time

Usbstor.sys

6.1.7600.16849

91,136

15-Jul-2011

03:30

Usbstor.sys

6.1.7600.21009

91,136

15-Jul-2011

03:34

Usbstor.sys

6.1.7601.17650

91,648

15-Jul-2011

03:39

Usbstor.sys

6.1.7601.21771

91,648

15-Jul-2011

03:23

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

File name

File version

File size

Date

Time

Usbstor.sys

6.1.7600.16849

238,592

15-Jul-2011

02:43

Usbstor.sys

6.1.7600.21009

239,104

15-Jul-2011

02:43

Usbstor.sys

6.1.7601.17650

238,592

15-Jul-2011

02:37

Usbstor.sys

6.1.7601.21771

239,616

15-Jul-2011

02:42

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

After you install this update, to increase the maximum transfer size of USB storage devices, follow these steps:

  1. Click Start start button , type regedit in the Start Search box, and then press Enter.

  2. Locate and then click the following registry subkey:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\usbstor\VVVVPPPP

  3. Click Edit, point to New, and then click DWORDValue.

  4. Type MaximumTransferLength, and then press Enter.

  5. Click Edit, and then click Modify.

  6. In the Value data box, type a value in the 64 KB-to-2 MB range. For example, select Decimal,and type a value in the range of 65535 (64 KB) to 2097120 (2 MB).

  7. Exit Registry Editor.

Notes

  • VVVV represents device descriptor idVendor in hexadecimal.

  • PPPP represents device descriptor idProduct in hexadecimal.


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_usbstor.inf_31bf3856ad364e35_6.1.7600.16849_none_488bef2ff902980f.manifest

File version

Not applicable

File size

2,087

Date (UTC)

15-Jul-2011

Time (UTC)

05:08

File name

X86_usbstor.inf_31bf3856ad364e35_6.1.7600.21009_none_4940a3cd11fffb57.manifest

File version

Not applicable

File size

2,087

Date (UTC)

15-Jul-2011

Time (UTC)

08:00

File name

X86_usbstor.inf_31bf3856ad364e35_6.1.7601.17650_none_4a5e79aff6393bdd.manifest

File version

Not applicable

File size

2,087

Date (UTC)

15-Jul-2011

Time (UTC)

04:58

File name

X86_usbstor.inf_31bf3856ad364e35_6.1.7601.21771_none_4ad376ed0f662ce0.manifest

File version

Not applicable

File size

2,087

Date (UTC)

15-Jul-2011

Time (UTC)

06:12

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

File name

Amd64_usbstor.inf_31bf3856ad364e35_6.1.7600.16849_none_a4aa8ab3b1600945.manifest

File version

Not applicable

File size

2,091

Date (UTC)

15-Jul-2011

Time (UTC)

06:04

File name

Amd64_usbstor.inf_31bf3856ad364e35_6.1.7600.21009_none_a55f3f50ca5d6c8d.manifest

File version

Not applicable

File size

2,091

Date (UTC)

15-Jul-2011

Time (UTC)

08:49

File name

Amd64_usbstor.inf_31bf3856ad364e35_6.1.7601.17650_none_a67d1533ae96ad13.manifest

File version

Not applicable

File size

2,091

Date (UTC)

15-Jul-2011

Time (UTC)

06:03

File name

Amd64_usbstor.inf_31bf3856ad364e35_6.1.7601.21771_none_a6f21270c7c39e16.manifest

File version

Not applicable

File size

2,091

Date (UTC)

15-Jul-2011

Time (UTC)

06:59

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

File name

Ia64_usbstor.inf_31bf3856ad364e35_6.1.7600.16849_none_488d9325f900a10b.manifest

File version

Not applicable

File size

2,089

Date (UTC)

15-Jul-2011

Time (UTC)

06:05

File name

Ia64_usbstor.inf_31bf3856ad364e35_6.1.7600.21009_none_494247c311fe0453.manifest

File version

Not applicable

File size

2,089

Date (UTC)

15-Jul-2011

Time (UTC)

08:44

File name

Ia64_usbstor.inf_31bf3856ad364e35_6.1.7601.17650_none_4a601da5f63744d9.manifest

File version

Not applicable

File size

2,089

Date (UTC)

15-Jul-2011

Time (UTC)

05:53

File name

Ia64_usbstor.inf_31bf3856ad364e35_6.1.7601.21771_none_4ad51ae30f6435dc.manifest

File version

Not applicable

File size

2,089

Date (UTC)

15-Jul-2011

Time (UTC)

07:25

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