Windows 8.1 Hyper-V network adapter is set to public and won't save as private

You can exclude certain nics from NLA (Network Location Awareness). Very common to do this in VMware workstation scenarios since the VMware nics always end up as unidentified/public. Here's how:

1. Navigate to:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002BE10318}
2. You will find enumerated keys like 0000, 0001, 0002 and so on.
3. Expend them one by one and look for DriverDesc REG_SZ value data.
4. In the same registry key where you found the name of the nic to exclude (DriverDesc value), create another new DWORD Value, name it *NdisDeviceType (it Case Sensitive!!). Double click on this value and in "Value Data" field put 1 as Decimal data

(snipped from) http://www.petri.co.il/forums/showthread.php?t=45181

You can set all unidentified networks as private via Group Policy:

gpedit.msc > Computer Configuration > Windows Settings > Security Settings > Network List Manager Policies > Unidentified Networks > Location type: Private