Hyper V R2 VM- Virtual Machine Bus/Network Card Missing

Techfella used Ask the Experts™
Hello- We were migrating some virtual machines from one san to another using SCVMM 2008 R2 using the "migrate storage" option of SCVMM. After the machine migrated, we turned it on and noticed that there were no network cards within the VM. We then checked the properties of the VM and sure enough, the VM had a virtual NIC attached with the correct MAC address and everything. When we go into device manager, there's no network card in device manager and we also notice that there's a problem with the virtual machine bus under the system devices section of device manager within the VM itself with the problem icon (yellow upside down triangle with exclamation mark in the middle. When we click the properties of the device, we get the message "A driver (service) for this device has been disabled. An alternate driver may be providing this functionality. Code (32)".

Can you please suggest what we can do to address this problem? We obviously can't run updates from within the VM because the network card is gone. We tried adding another one and it installed but failed to start.

Thanks in advance.
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2008 R2 VM virtual bus


Can I suggest with one VM first, to change the MAC from static to dynamic first, then fire up the VM. Does this solve the problem?

If not, in SCVMM while the VM is off, right click and 'Install virtual guest services'. This will update the integration services in the VM and its ability to talk to the host.

Let me know how you get on.
Hi Netflo- actually we found the solution and it was so simple its almost embarassing. We deleted the VM bus in the virtual machine under device manager, scanned for new hardware and that fixed the problem- thanks.

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