This article describes an issue that occurs after the live migration is complete in Windows Server 2012 R2 or Windows Server 2008 R2. A hotfix is available to resolve this issue. The hotfix has a prerequisite.

Symptoms

Consider the following scenario:

  • You have a Hyper-V cluster that is running on Windows Server 2008 R2 or a later version of Windows Server.

  • You configure Windows Network Load Balancing (NLB) on two or more virtual machines that are running Windows Server 2012 R2 or Windows Server 2008 R2. The virtual machines are hosted on the same cluster node.

  • You move the NLB virtual machines by concurrent live migration.

  • The live migration is complete.

In this scenario, one or more nodes on the NLB cluster go into a misconfigured status that can be seen in Network Load Balancing Manager. Additionally, you may receive an error message that resembles the following on the misconfigured node:


Windows has detected an IP address conflict
Another computer on this network has the same IP address as this computer. Contact your network administrator for help resolving this issue. More details are available in the Windows System event log.

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 this specific problem.

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, submit a request to 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 have update 2919355 installed in Windows Server 2012 R2. Or, you must install Service Pack 1 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 may have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

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 Server 2012 R2 file information and notes

Important Windows 8.1 hotfixes and Windows Server 2012 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 8.1/Windows Server 2012 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, 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

    6.3.960 0.17 xxx

    Windows Server 2012 R2

    RTM

    GDR

  • GDR service branches contain only those fixes that are widely released to address widespread, critical issues. LDR service branches contain hotfixes in addition to widely released fixes.

  • 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 2012 R2" section. MUM, MANIFEST, and the associated security catalog (.cat) files, are very 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 Server 2012 R2

File name

File version

File size

Date

Time

Platform

Nlb.sys

6.3.9600.17627

336,896

07-Jan-2015

05:13

x64

Windows Server 2008 R2 file information and 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, 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 1.22xxx

    Windows Server 2008 R2

    SP1

    LDR

  • GDR service branches contain only those fixes that are widely released to address widespread, critical issues. LDR service branches contain hotfixes in addition to widely released fixes.

  • 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" section. MUM, MANIFEST, and the associated security catalog (.cat) files, are very 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 Server 2008 R2

File name

File version

File size

Date

Time

Platform

Nlb.sys

6.1.7601.22891

340,992

04-Dec-2014

02:19

x64

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

File name

File version

File size

Date

Time

Platform

Nlb.sys

6.1.7601.22891

783,360

04-Dec-2014

01:34

IA-64

Additional file information

Additional file information for Windows Server 2012 R2

Additional files for all supported x64-based versions of Windows Server 2012 R2

File property

Value

File name

Amd64_2f4483518eff3cb0587740c4dfc16587_31bf3856ad364e35_6.3.9600.17628_none_7a7482b284875787.manifest

File version

Not applicable

File size

726

Date (UTC)

10-Jan-2015

Time (UTC)

02:47

File name

Amd64_microsoft-windows-n..ncing-networkdriver_31bf3856ad364e35_6.3.9600.17628_none_9f0d277eec2ccce0.manifest

File version

Not applicable

File size

2,708

Date (UTC)

08-Jan-2015

Time (UTC)

00:53

Additional file information for Windows Server 2008 R2

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

File property

Value

File name

Amd64_b360d18bd0d7eeabac79e543bf066dcd_31bf3856ad364e35_6.1.7601.22891_none_93dfcc9077da4026.manifest

File version

Not applicable

File size

726

Date (UTC)

04-Dec-2014

Time (UTC)

09:07

File name

Amd64_microsoft-windows-n..ncing-networkdriver_31bf3856ad364e35_6.1.7601.22891_none_0c6006da486ac91d.manifest

File version

Not applicable

File size

2,669

Date (UTC)

04-Dec-2014

Time (UTC)

05:34

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

File property

Value

File name

Ia64_cf64acd5589e777aa442f31574dbe0d4_31bf3856ad364e35_6.1.7601.22891_none_7e7c84301ac265eb.manifest

File version

Not applicable

File size

724

Date (UTC)

04-Dec-2014

Time (UTC)

09:07

File name

Ia64_microsoft-windows-n..ncing-networkdriver_31bf3856ad364e35_6.1.7601.22891_none_b0430f4c900b60e3.manifest

File version

Not applicable

File size

2,667

Date (UTC)

04-Dec-2014

Time (UTC)

05:36



Status

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

References

See the terminology that Microsoft uses to describe software updates.

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