November 28, 2010

Why can't I see the unconnected devices (eg network adapters) in Device Manager?

I bumped into this issue while I was using VMConverter to move a VM from my ESX 3.5 server to another ESX 4 host (there are some other issues along the way, which I will probably create a separate thread for upgrading of VMs). 

I had upgraded the VM to Virtual Machine version 7. The old virtual NIC did not show up in Network Connections anymore. I added a new virtual NIC and tried to assign the old IP, but kept receiving the error that an existing NIC with the same IP has been assigned. Well, I can force it to accept because I know the old one is already disabled and redundant as a result of the VM upgrade, but to make a clean upgrade, I had still wanted to remove the old NIC totally. Also, previously we had some issues with lingering old NIC drivers that caused instability in the server.

Removal was not possible because in the Device Manager, I could not see the old NIC there even after turning on hidden devices. Turns out that this was a design by Microsoft to prevent "phantom" or disconnected devices from showing up in Device Manager.

Further discussion by Microsoft here.




Symptoms
  • Disconnected or "phantom" devices do not show up in Device Manager
  • Enabling "Show hidden devices" in Device Manager also does not reveal the devices

To resolve
  1. Command prompt -> set devmgr_show_nonpresent_devices=1
  2. Command prompt -> start devmgmt.msc
  3. Device Manager -> View -> Show hidden devices

Those hidden devices will show up in a "greyed out" form.






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