The MPIO failover process does not complete on a Windows Server 2008-based computer that uses Microsoft Device Specific Module for MPIO

Applies to: Windows Server 2008 StandardWindows Server 2008 EnterpriseWindows Server 2008 Datacenter


Consider the following scenario:
  • You connect a Windows Server 2008-based computer to a storage device that is controlled by Microsoft Multipath I/O (MPIO).
  • A failover occurs on the MPIO paths.
In this scenario, the failover process does not complete. Additionally, all MPIO-related operations stop responding.


This problem occurs because the MPIO.sys driver does not decrement an I/O count correctly.


Hotfix information

Important Windows Vista and Windows Server 2008 hotfixes are included in the same packages. However, only one of these products may be listed on the “Hotfix Request” page. To request the hotfix package that applies to both Windows Vista and Windows Server 2008, just select the product that is listed on the page.

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.


No prerequisites are required.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The Global version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Vista and Windows Server 2008 file information notes

  • The files that apply to a specific product, SR_Level (RTM,SPn), and service branch (LDR, GDR) can be identified by examining the fileversion numbers as shown in the following table.
    VersionProductSR_LevelService branch
    6.0.6000.16xxxWindows VistaRTMGDR
    6.0.6000.20xxxWindows VistaRTMLDR
    6.0.6001.18xxxWindows Vista and Windows Server 2008SP1GDR
    6.0.6001.22xxxWindows Vista and Windows Server 2008SP1LDR
    6.0.6002.18xxxWindows Vista and Windows Server 2008SP2GDR
    6.0.6002.22xxxWindows Vista and Windows Server 2008SP2LDR
  • Service Pack 1 is integrated into Windows Server 2008.
  • The MANIFEST files (.manifest) and MUM files (.mum)installed for each environment are listed separately. MUM and MANIFEST files, andthe associated security catalog (.cat) files, are critical to maintaining thestate of the updated component. The security catalog files (attributes notlisted) are signed with a Microsoft digital signature.
For all supported x86-based versions of Windows Server 2008
File nameFile versionFile sizeDateTimePlatform
Mpio.infNot Applicable3,76029-Apr-200909:00Not Applicable
Mpio.infNot Applicable3,76029-Apr-200908:57Not Applicable
For all supported x64-based versions of Windows Server 2008
File nameFile versionFile sizeDateTimePlatform
Mpio.infNot Applicable3,76829-Apr-200909:01Not Applicable
Mpio.infNot Applicable3,76829-Apr-200908:57Not Applicable
For all supported Itanium-based versions of Windows Server 2008
File nameFile versionFile sizeDateTimePlatform
Mpio.infNot Applicable3,76429-Apr-200908:58Not Applicable
Mpio.infNot Applicable3,76429-Apr-200908:57Not Applicable


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

Additional file information for Windows Server 2008

Additional files for all supported x86-based versions of Windows Server 2008

File nameFile versionFile sizeDateTimePlatform
Package_for_kb968287_sc_0~31bf3856ad364e35~x86~~ Applicable1,42130-Apr-200907:28Not Applicable
Package_for_kb968287_sc_1~31bf3856ad364e35~x86~~ Applicable1,69030-Apr-200907:28Not Applicable
Package_for_kb968287_sc~31bf3856ad364e35~x86~~ Applicable1,70130-Apr-200907:28Not Applicable
Package_for_kb968287_server_0~31bf3856ad364e35~x86~~ Applicable1,42530-Apr-200907:28Not Applicable
Package_for_kb968287_server_1~31bf3856ad364e35~x86~~ Applicable1,69430-Apr-200907:28Not Applicable
Package_for_kb968287_server~31bf3856ad364e35~x86~~ Applicable1,71330-Apr-200907:28Not Applicable
X86_mpio.inf_31bf3856ad364e35_6.0.6001.22422_none_1da8dfd4a880413d.manifestNot Applicable1,65930-Apr-200907:33Not Applicable
X86_mpio.inf_31bf3856ad364e35_6.0.6002.22125_none_1f92529aa5a3e266.manifestNot Applicable1,65930-Apr-200907:33Not Applicable

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

File nameFile versionFile sizeDateTimePlatform
Amd64_mpio.inf_31bf3856ad364e35_6.0.6001.22422_none_79c77b5860ddb273.manifestNot Applicable1,66130-Apr-200907:37Not Applicable
Amd64_mpio.inf_31bf3856ad364e35_6.0.6002.22125_none_7bb0ee1e5e01539c.manifestNot Applicable1,66130-Apr-200907:37Not Applicable
Package_for_kb968287_sc_0~31bf3856ad364e35~amd64~~ Applicable1,42930-Apr-200907:28Not Applicable
Package_for_kb968287_sc_1~31bf3856ad364e35~amd64~~ Applicable1,70230-Apr-200907:28Not Applicable
Package_for_kb968287_sc~31bf3856ad364e35~amd64~~ Applicable1,71130-Apr-200907:28Not Applicable
Package_for_kb968287_server_0~31bf3856ad364e35~amd64~~ Applicable1,43330-Apr-200907:28Not Applicable
Package_for_kb968287_server_1~31bf3856ad364e35~amd64~~ Applicable1,70630-Apr-200907:28Not Applicable
Package_for_kb968287_server~31bf3856ad364e35~amd64~~ Applicable1,72330-Apr-200907:28Not Applicable

Additional files for all supported Itanium-based versions of Windows Server 2008

File nameFile versionFile sizeDateTimePlatform
Ia64_mpio.inf_31bf3856ad364e35_6.0.6001.22422_none_1daa83caa87e4a39.manifestNot Applicable1,66030-Apr-200907:28Not Applicable
Ia64_mpio.inf_31bf3856ad364e35_6.0.6002.22125_none_1f93f690a5a1eb62.manifestNot Applicable1,66030-Apr-200907:28Not Applicable
Package_for_kb968287_sc_0~31bf3856ad364e35~ia64~~ Applicable1,42530-Apr-200907:28Not Applicable
Package_for_kb968287_sc_1~31bf3856ad364e35~ia64~~ Applicable1,52930-Apr-200907:28Not Applicable
Package_for_kb968287_sc~31bf3856ad364e35~ia64~~ Applicable1,70630-Apr-200907:28Not Applicable
Package_for_kb968287_server_0~31bf3856ad364e35~ia64~~ Applicable1,42930-Apr-200907:28Not Applicable
Package_for_kb968287_server_1~31bf3856ad364e35~ia64~~ Applicable1,53330-Apr-200907:28Not Applicable
Package_for_kb968287_server~31bf3856ad364e35~ia64~~ Applicable1,71730-Apr-200907:28Not Applicable