The virtual machine network fails if the "minimum bandwidth weight" setting is enabled in Windows Server 2012

View products that this article applies to.

Symptoms

Consider the following scenario:

You have Virtual Machine Manager for Microsoft System Center 2012 installed on a Windows Server 2012 Hyper-V host.
You add a third-party virtual network switch extension to System Center 2012 Service Pack 1 (SP1) Virtual Machine Manager or to System Center 2012 R2 Virtual Machine Manager.
One of the following conditions is true:
- You apply the MinimumBandwidthWeight setting to the network of a Hyper-V virtual machine.
- You use the System Center Virtual Machine Manager "high bandwidth adapter" or "medium bandwidth adapter" native port profile.

In this scenario, external communication from the virtual machine network fails.

Resolution

Hotfix information

A supported hotfix is available from Microsoft Support. 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, go to the following Microsoft website:

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 have Windows Server 2012 installed.

Restart requirement

You do not have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any previously released hotfix.

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File information

The English (United States) 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 file information and notes

Important Windows 8 and Windows Server 2012 hotfixes are included in the same packages. However, only "Windows 8" is listed on the Hotfix Request page. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows 8" on the page. Always refer to the "Applies t" 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
6.2.920 0.16xxx Windows Server 2012 RTM GDR
6.2.920 0.20xxx Windows Server 2012 RTM 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 2012" 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.

Version	Product	Milestone	Service branch
6.2.920 0.16xxx	Windows Server 2012	RTM	GDR
6.2.920 0.20xxx	Windows Server 2012	RTM	LDR

For all supported x64-based versions of Windows Server 2012

File name	File version	File size	Date	Time	Platform
Vmsif.dll	6.2.9200.16384	46,080	26-Jul-2012	03:07	x64
Vmsntfy.dll	6.2.9200.16384	89,088	26-Jul-2012	03:07	x64
Vmswitch.sys	6.2.9200.20978	566,784	01-Mar-2014	07:29	x64
Vmsif.dll	6.2.9200.16384	46,080	26-Jul-2012	03:07	x64
Vmsntfy.dll	6.2.9200.16384	89,088	26-Jul-2012	03:07	x64
Vmswitch.sys	6.2.9200.20978	566,784	01-Mar-2014	07:29	x64

Additional file information

Additional file information for Windows Server 2012

Additional files for all supported x64-based versions of Windows 8

File name	Amd64_2849cdee54e964621547b2eed3d838d3_31bf3856ad364e35_6.2.9200.20978_none_74aed61a5f32b1b9.manifest
File version	Not Applicable
File size	708
Date (UTC)	04-Mar-2014
Time (UTC)	19:02
SHA-1 hash	Not Applicable
MD5 hash	Not Applicable

File name	Amd64_microsoft-hyper-v-drivers-vmswitch_31bf3856ad364e35_6.2.9200.20978_none_c26d584522f2f960.manifest
File version	Not Applicable
File size	162,594
Date (UTC)	04-Mar-2014
Time (UTC)	19:02
SHA-1 hash	Not Applicable
MD5 hash	Not Applicable

File name	Amd64_wvms_pp.inf_31bf3856ad364e35_6.2.9200.20978_none_bc47b21f94387254.manifest
File version	Not Applicable
File size	3,379
Date (UTC)	04-Mar-2014
Time (UTC)	19:02
SHA-1 hash	Not Applicable
MD5 hash	Not Applicable