When replacing a motherboard or a network card, during a P2V or cold migration of virtual machines between hypervisors/sites, or when configuring multiple VLANs on a single NIC in Windows, you can come across a problem of hidden (ghost) network adapters. In this case, you cannot set the previously assigned static IP address for a new network interface.
Windows automatically hides the devices that are present in Windows configuration, but are not physically connected to the computer. The hidden network adapter in Windows remains if you physically disconnect the previously installed network card (this can be either a physical NIC or a virtual network adapter). The previously installed network card becomes hidden and you cannot see it in the Device Manager.
Error: The IP Address Already Assigned to Another Network Adapter
The main problem of hidden network adapters is that you cannot assign an IP address of your old network adapter to a new network card. When you try to assign the old IP address, the following warning appears:
Microsoft TCP/IP The IP address <IP address> you have entered for this network adapter is already assigned to another adapter (Intel Gigabit Network Connection) which is no longer present on the computer. If the same address is assigned to both adapters and they both become active, only one of them will use this address. This may result in incorrect system configuration. Do you want to fix the problem by entering a different IP address for this adapter in the list of IP addresses in the Advanced dialog box?
I often come across this issue in VMWare virtual machines with a VMXNet3 virtual network adapter. A new virtual NIC card is identified as a new device (unlike vNIC type E1000). If you have removed a network card (vNIC) on a VMWare virtual machine and added a new one, you won’t be able to set your old IP address assigned to the removed network interface.
Also, the problem of hidden network adapters appears after migrating a physical server to a VM (Physical-to-Virtual — P2V), for example, using the VMware Converter. After the migration, disabled (physical) network adapters still remain in Windows, and you cannot use the old IP address settings for the new vNICs.
Prior to assigning an old IP address to a new network adapter, you must remove the configuration of disconnected NICs.
How to Remove a Non-Existent Network Card Using the Device Manager?
To uninstall hidden (physically removed) network adapters in Windows, open the Device Manager console in the special mode.
To do it in Windows 7 (or earlier):
- Open the command prompt as an administrator;
- Run the command:
set devmgr_show_nonpresent_devices=1
- Start the Device Manager console:
devmgmt.msc
In the top menu, click View -> Show hidden devices (in Windows 10 this item is always available, and you don’t need to enable the devmgr_show_nonpresent_devices mode via cmd).
Expand the Network adapters section. Hidden network cards should appear in the list (they have pale icons). Select the network card you want to remove, right-click it -> Uninstall Device.
Remove Network Adapter Settings from the Registry
If after removing an unused NIC in the Device Manager you still cannot assign the old IP address to a new adapter, remove the IP configuration of the old NIC from the registry.
The IP settings of your network interfaces are located under the registry key HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces.
This registry keys contains some {Interface GUID} keys. Check them one-by-one until you find the interface, which IPAddress value contains the IP address assigned to the old network interface. The IPAddress parameter may contain more than one IP address, since in Windows you can assign multiple IP addresses (aliases) to a single network adapter.
Remember the name of the registry key (it is the identifier of the network adapter). Remove the keys:
- HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Adapters\{your_NIC_ID}
- HKLM\SYSTEM\CurrentControlSet\Services\{your_NIC_ID}
Restart your computer and try to assign the old static IP address to a new network adapter.
It is also recommended to reset your network. In Windows 10, you can do it in Settings -> Network and Internet -> Network Reset.
If you face the problem after you installed an additional network card in your computer, make sure that the built-in LAN interface is disabled in BIOS/UEFI settings (the related item is usually called Onboard Gbit NIC or Onboard LAN).