Hyper-V Guest: Network cable unplugged

Question

Scenario

• Dell Latitude E6430
• Windows 10 Anniversary Update running on bare metal
• Installed Hyper-V
• Created External Hyper-V Virtual Switch
• Created Hyper-V Guest (Generation 2): Windows Server 2016 Technical Preview 5 (TP5)

Symptom

The Windows Server 2016 Technical Preview 5 (TP5) Hyper-V guest is reporting that its network cable is unplugged.

What I've Tried

• Remove the Network Adapter from the Hyper-V Guest
• Remove the Hyper-V External Virtual Switch
• Create a new Hyper-V External Virtual Switch
• Add a Network Adapter to the Hyper-V Guest (bound to External VSwitch)
• The problem persists

Question

What's wrong, how can I diagnose the root cause, and fix it?

Solution 1

Be sure to check if you have selected the right network card (LAN or wireless LAN card) for the virtual switch to which your guest is connected. Follow the link below for reference

Solution 2

In most cases, if the VM guest shows that the Ethernet cable is disconnected, it means that in the settings for the VM the Network Adapter's virtual switch is set to "Not connected." Obviously this doesn't seem to be the case for you, but double check to be safe.

Now, to find the cause of the problem, I would make 3 networks in the Virtual Switch Manager. One private, one internal, and one external. Try connecting it to all three and see if anything changes. You should be able to do this while the VM is running.

If something changes, (e.g. You get a connected message on the internal network) remove your external network (From Hyper-V altogether), and try bridging the Network adapters (real ethernet and internal network) in the Host machine. (This may or may not work, and it may or may not be a good idea, but chances are it will give you more information for determining where exactly the problem lies.)

If nothing changes (e.g. it doesn't matter what network you connect to), try making a different VM (like some linux distro or something. Maybe Ubuntu Desktop?) and see if you get similar results. (with its network adapter connected to the private, internal, and external networks)

If you do get similar results with the linux distro, then I'd say it's safe to say it's a problem with Hyper-V and I'd try completely removing it as a feature, and re-adding it. If you do not get similar results with the linux distro (e.g. it works), then it's likely your VM itself, and I'd try removing the Hyper-V drivers and reinstalling them (Which will be a trick without internet, and would probably need it's own question)

In any case, after you've tried all this, if you're still having a problem, update your question with the new information you've gained and maybe someone else can add more.