A disabled Hyper-V virtual network adapter is re-enabled after you install Windows Server 2008 Service Pack 2

Consider the following scenario.

• You have the release version of Hyper-V installed on a computer that is running Windows Server 2008.
• You create an external virtual network in Hyper-V Manager.
• You disable the virtual network adapter in the management operating system.
• You install Windows Server 2008 Service Pack 2 (SP2) in the management operating system.

In this scenario, the virtual network adapter that you disabled in the management operating system is now enabled.

This issue occurs because the network adapters in the management operating system are re-created when Windows Server 2008 SP2 is applied, and the previous state of the adapters is not migrated.

To resolve this issue, use one of the following methods.

Method 1: Full installation of Windows Server 2008

To disable the virtual network adapter in a full installation of Windows Server 2008, follow these steps:

1. Open Network and Sharing Center in Control Panel.
2. Click Manage Network Connections.
3. On the View menu, click Details.
4. Double-click the appropriate virtual network adapter in the Name column.
   
   Note In a default installation, this is the name of the External Virtual Network that was created by Virtual Network Manager in Hyper-V Manager.
5. Click Disable.

Method 2: Server core installation of Windows Server 2008

To disable the virtual network adapter in a server core installation of Windows Server 2008, open a command prompt, and then type the following commands. Press ENTER after each command. Note The InterfaceName placeholder is the Interface name that is displayed by the first command.

We recommend that you take the following actions:

• Create external virtual networks that do not have to have connectivity in the management operating system.
• Create these networks without a virtual network adapter within the management operating system in which they are created.

To do this by using the Hyper-V WMI APIs, visit the following Microsoft MSDN Blogs Web site: