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Article ID: 2581464 - Last Review: December 27, 2012 - Revision: 4.0

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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=support (http://support.microsoft.com/contactus/?ws=support)
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 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  (http://support.microsoft.com/kb/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.
    Collapse this tableExpand this table
    VersionProductSR_LevelService branch
    6.1.760 0 . 16xxxWindows 7 and Windows Server 2008 R2RTMGDR
    6.1.760 0 . 21xxxWindows 7 and Windows Server 2008 R2RTMLDR
    6.1.760 1 . 17xxxWindows 7 and Windows Server 2008 R2SP1GDR
    6.1.760 1 . 21xxxWindows 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 x86-based versions of Windows 7
Collapse this tableExpand this table
File nameFile versionFile sizeDateTime
Usbstor.sys6.1.7600.1684975,77615-Jul-201103:01
Usbstor.sys6.1.7600.2100975,77615-Jul-201102:58
Usbstor.sys6.1.7601.1765076,28815-Jul-201102:55
Usbstor.sys6.1.7601.2177176,28815-Jul-201103:53
For all supported x64-based versions of Windows 7 and of Windows Server 2008 R2
Collapse this tableExpand this table
File nameFile versionFile sizeDateTime
Usbstor.sys6.1.7600.1684991,13615-Jul-201103:30
Usbstor.sys6.1.7600.2100991,13615-Jul-201103:34
Usbstor.sys6.1.7601.1765091,64815-Jul-201103:39
Usbstor.sys6.1.7601.2177191,64815-Jul-201103:23
For all supported IA-64–based versions of Windows Server 2008 R2
Collapse this tableExpand this table
File nameFile versionFile sizeDateTime
Usbstor.sys6.1.7600.16849238,59215-Jul-201102:43
Usbstor.sys6.1.7600.21009239,10415-Jul-201102:43
Usbstor.sys6.1.7601.17650238,59215-Jul-201102:37
Usbstor.sys6.1.7601.21771239,61615-Jul-201102:42

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  (http://support.microsoft.com/kb/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
    Collapse this imageExpand this image
    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
Collapse this tableExpand this table
File nameX86_usbstor.inf_31bf3856ad364e35_6.1.7600.16849_none_488bef2ff902980f.manifest
File versionNot applicable
File size2,087
Date (UTC)15-Jul-2011
Time (UTC)05:08
File nameX86_usbstor.inf_31bf3856ad364e35_6.1.7600.21009_none_4940a3cd11fffb57.manifest
File versionNot applicable
File size2,087
Date (UTC)15-Jul-2011
Time (UTC)08:00
File nameX86_usbstor.inf_31bf3856ad364e35_6.1.7601.17650_none_4a5e79aff6393bdd.manifest
File versionNot applicable
File size2,087
Date (UTC)15-Jul-2011
Time (UTC)04:58
File nameX86_usbstor.inf_31bf3856ad364e35_6.1.7601.21771_none_4ad376ed0f662ce0.manifest
File versionNot applicable
File size2,087
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
Collapse this tableExpand this table
File nameAmd64_usbstor.inf_31bf3856ad364e35_6.1.7600.16849_none_a4aa8ab3b1600945.manifest
File versionNot applicable
File size2,091
Date (UTC)15-Jul-2011
Time (UTC)06:04
File nameAmd64_usbstor.inf_31bf3856ad364e35_6.1.7600.21009_none_a55f3f50ca5d6c8d.manifest
File versionNot applicable
File size2,091
Date (UTC)15-Jul-2011
Time (UTC)08:49
File nameAmd64_usbstor.inf_31bf3856ad364e35_6.1.7601.17650_none_a67d1533ae96ad13.manifest
File versionNot applicable
File size2,091
Date (UTC)15-Jul-2011
Time (UTC)06:03
File nameAmd64_usbstor.inf_31bf3856ad364e35_6.1.7601.21771_none_a6f21270c7c39e16.manifest
File versionNot applicable
File size2,091
Date (UTC)15-Jul-2011
Time (UTC)06:59
Additional files for all supported IA-64–based versions of Windows Server 2008 R2
Collapse this tableExpand this table
File nameIa64_usbstor.inf_31bf3856ad364e35_6.1.7600.16849_none_488d9325f900a10b.manifest
File versionNot applicable
File size2,089
Date (UTC)15-Jul-2011
Time (UTC)06:05
File nameIa64_usbstor.inf_31bf3856ad364e35_6.1.7600.21009_none_494247c311fe0453.manifest
File versionNot applicable
File size2,089
Date (UTC)15-Jul-2011
Time (UTC)08:44
File nameIa64_usbstor.inf_31bf3856ad364e35_6.1.7601.17650_none_4a601da5f63744d9.manifest
File versionNot applicable
File size2,089
Date (UTC)15-Jul-2011
Time (UTC)05:53
File nameIa64_usbstor.inf_31bf3856ad364e35_6.1.7601.21771_none_4ad51ae30f6435dc.manifest
File versionNot applicable
File size2,089
Date (UTC)15-Jul-2011
Time (UTC)07:25

Applies to
  • Windows 7 Starter
  • Windows 7 Home Premium
  • Windows 7 Home Basic
  • Windows 7 Professional
  • Windows 7 Enterprise
  • Windows 7 Ultimate
  • Windows Server 2008 R2 Standard
  • Windows Server 2008 R2 Foundation
  • Windows Server 2008 R2 Enterprise
  • Windows Server 2008 R2 Datacenter
  • Windows Server 2008 R2 for Itanium-Based Systems
Keywords: 
kbautohotfix kbqfe kbhotfixserver kbfix kbsurveynew kbexpertiseinter kbexpertiseadvanced KB2581464
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