Thursday, September 17, 2009

HyperV networking works on Server 2008 R2 guest but not Server 2008 guest

The Scenario:

Hyper-V R2 (Server 2008 R2) host, Server 2008 guest (not R2), Server 2008 R2 guest

The situation plays out like this:

I create a VM and install Server 2008 R2 Standard.

The external network, connecting me to the internet, works fine and the guest OS automatically has a working network device and connection.

I shut down this VM and leave it off.

I then create another VM, exactly the same, choosing the same external network as above. This time I install Server 2008 Standard (non-R2).

The server does not find its network card, and therefore cannot connect to the internet. When I look at the guest OS, there is a yellow splat in the device manager for the virtual network adapter.


My first question in response to this:

Did you install the Integration Components within the VM?


Here is why:
Server 2008 has the ICs built in to the OS (they are extremely similar to device drivers).

But, versioning issues can come into play - the host and guest must match for optimum performance.

With the release of R2 the ICs included backward compatibility - thus allowing an R2 VM to 'just work' when you install it onto a Hyper-V v1 (2008, but not 2008 R2) host.

Now, when you have a Server 2008 VM on an R2 host - the VM built-in ICs are older than the host ICs - thus the ICs in the VM need to be updated.

Using the Hyper-V manager Console, open the console of the VM and choose Action, Install Integration Services - then respond to any prompts.

Thank you “Kelly AZ” for describing this problem so well in the TechNet forum.


Arian said...


I have Windows Server 2008 non R2 with HyperV.
In the HyperV I have Win7 installed.
On the Event Logs I get this error:

"Device 'VMBus' in 'Win7' cannot load because it is incompatible with virtualization stack. Server version 13 Client version 65537 (Virtual machine D6D7F94F-A9E8-40FF-A98D-5B3C087AB5BE)."

Source: Hyper-V-Worker
Event ID: 23012
Level: Error

I have read your post. Isn't it possible to update the VMBus on the Hostmachine to the version of which it has Win7?
Or have I to downgrade the version of Win7 to this on W2K8 non R2?

Have you any idea how to fix it?


BrianEh said...

You are essentially running an R2 guest on a v1 host.

A songle componenet of hte hypervisor cannot be upgraded, only the entire thing.

The solutions are:
- downgrade the ICs in the guest.
- upgrade to Hyper-V R2

MSFT would like you to upgrade to R2, for many reasons, not money.

Personally, I agree, upgrade to R2 - there are many things that are improved.