Microsoft has released a hotfix for when you cannot add network adapters to a virtual machine on a Windows Server 2008 R2-based failover cluster.
Consider the following scenario:
- You create a failover cluster on some computers that are running Windows Server 2008 R2 SP1.
- You enable the Hyper-V role on both cluster nodes.
- You configure a virtual machine as a cluster resource.
- You try to add a network adapter to the virtual machine by using the Refresh Virtual Machine Configuration wizard.
In this scenario, you cannot add the network adapter successfully until the virtual machine is removed from the cluster.
A supported hotfix is available from Microsoft.