Hi I'm not very familiar with Hyper-V but after setting up a Hyper-V server and then removing the Hyper-V Role from my Windows 2012 R2 server, it seems like one Network adapter has stopped working. I have a good switchport and cable (verified) and when I plug into this port, I see the network adapter in Control panel showing as cable is unplugged.  I then moved to another Windows 2012 server and installed Hyper-V role and setup a virtual server, then removed the server and the role and ended up with the same problem on the second server. it seems like Hyper-V's virtual switch is still holding on to this NIC port. Anyone knows how to free up this port?

Thank you

Just out of interest, have you tried disabling the NIC (leave for five or ten minutes, press F5 in the Adapter Settings window and then enable the NIC)? 

How are you removing the Hyper-V role? 

Also, when configuring the switches, what type of switches are you configuring and did you delete the switch before removing the Hyper-V role?

Hyper-V does not "hang on to" the physical switch, except in very rare cases where SR-IOV has been utilized.

Yes I disabled the NIC's over night and enabled. I've uninstalled and reinstalled as well. It was the default switch Hyper-V created, I didn't create anything. I removed the Hyper-V role from add / remove roles.

Hum... is the device present and correct in the Device Manager? 

If so, maybe try resetting:

at the command prompt (as administrator):

netsh int ipv4 reset reset.log

netsh int ipv6 reset reset.log

maybe try:

netsh winsock reset catalog

If this doesn't work, try uninstalling the NIC from the Device Manager and then right click the computer/server and select look for hardware changes. 

(I'm assuming this is not a production server?)

Have you looked at:

https://technet.microsoft.com/en-us/library/mt126106.aspx

to see fi there is anything in there that may be of help?

Yes, this server is not in service yet. Yes the device is present and configured just like the other 3 Broadcom NIC's. I think I'm just going to wipe the server out and install the OS fresh. Even though I really like to find out what the problem is, I'm pressed for time.

Thank you for your suggestions.

Did you reboot the server after removing the Hyper-V role?

That's probably the best way to go. 

Before reinstalling I always wipe the disk and remove formatting, letters etc.  GParted is an excellent tool for this.  For the more difficult cases, I will reset the BIOS as well, just because...

Just an FYI .. I decided to install the Hyper-V roll without the VMs and all ports started working.