Some VM don't recognize virtual network cards

Question

Hi all,
I have an hyper-v install with a dell T320 server with two ethernet cards from Broadcom and Windows Server 2012 R2 as hyper-v server.
I have one VM with 2012 R2 and one another host with 2012 Std. All the systems are working fine since we make the install.
Since this morning I see that the 2012 Std server is not able to connect to the network.
I shutdown all VMs, delete the Vswitch, delete the physical network card, restart the host, recreate a new vswitch and reconnect the VMs to it. I access the network on 2012 R2 but in 2012 Std the OS see no network card.
What can I do.

Answer 1

Hi Derick,
Please try following steps :
1. Configure Device Manager in the VM to show hidden devices (the article says it is for XP but it works on all Windows OS')
https://support.microsoft.com/kb/315539
2. Delete all virtual NICs and when you delete the last one, also delete the driver when prompted.
3. Shut down the VM.
4. Remove the NIC from the VM settings.
5. Start the VM with no NIC.
6. Log in to the VM, then shut it down again.
7. Add a NIC back to the VM.
8. Start the VM again.
9. Configure the new NIC with a static IP.
10. Reboot and see if that resolves the problem.
If it still doesn't work , I would suggest you to attach the problematic VM's VHD file to a new VM .
Best Regards,
Elton Ji
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