Hidden Network Devices

One annoying thing about working with Hyper-V  is you can end up with lots of “hidden” network devices. For example:

a) If you installed using a RIS server and legacy NIC
b) If you moved a VHD between servers, the NIC gets a new MAC address and device
c) If you use clustering and haven’t got the network setup identically  on all nodes

d) If you use clustering and accidently use the old Hyper-V Manager instead of cluster manager

To remove the hidden NIC’s the steps are:
1) Add system environment variable DEVMGR_SHOW_NONPRESENT_DEVICES with a value of 1

2) Open up device manager and select “show hidden” devices, then delete the offending NIC’s.

You can see how these invisible NIC’s clutter up tools like “bginfo” that show the system summary data by adding extra NIC’s with settings of “none” (see the DNS Server entries below)