Hyper-v virtual switch breaks my network

Glad to find this, and surprised an issue of this nature is still not fixed. I notice one work-around is missing from this thread, so thought I would add it:

The problem: Creation of a new external virtual switch in HyperV Manager causes Host file sharing to be disrupted. Specifically, it appears that the services associated with physical adapters get set correctly, but something below the hood for File and Print Sharing gets broken.

Solutions:
As said in earlier posts, if the new "Default Switch" works for you, it is the least problematic option. Delete any manually created external virtual switches and set the network adapter for each VM to "Default Switch" to take this option.

Unfortunately, you cannot assign a distinct IP address to the Default Switch. So this may not work for all users.

Another option not discussed yet works for users with multiple physical network connections. You can use one physical adapter for the host machine, and a different one for the virtual switch. When creating the virtual switch, uncheck the box to allow the host machine to share the connection.

You'll notice that even though this setup has the virtual switch completely separated from the host machine's networking, the host machine's file sharing still gets broken. However, simply get properties of the physical network adapter for the host machine, remove all protocols and apply. Then add them back and apply. This will restore functionality.

Some have noted that they had to redo this every time they restarted their machine. I haven't confirmed this yet, but it is likely. Ugh.

This solution will did not work for me with a single physical network shared with the host machine. It required adding an Ethernet port. I think if I had only one port, I would use Kari's suggestion from post #18 above.

i am having nearly the same issue and it's driving me NUTS lol. I wish there was a permanent fix. I was having trouble confirming whether the issue is with Windows 10 - 1803 or possibly my intel ac 8265 nic. What type of nic are you guys using?

I may have found another workaround. If your using an external network adapter, go into the properties of that adapter and uncheck "File and Printer Sharing For Microsoft Networks" and click ok. Then go back and re-check "File and Printer Sharing For Microsoft Networks." When doing this it appears to have temporarily fixed the issue. File Sharing works on he host and from the VM. Although after a reboot as others have mentioned the issue returns and you have to repeat this process.

tonight I created a powershell script that disables and then enables the File and Printer Sharing For Microsoft Networks binding on a Hyper-V adapter. So far has worked everything the file sharing goes down. I think this also isolates what's causing the issue at least in my case. Let me know if it works for anyone else.

if (!([Security.Principal.WindowsPrincipal][Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole] "Administrator")) { Start-Process powershell.exe "-NoProfile -ExecutionPolicy Bypass -File `"$PSCommandPath`"" -Verb RunAs; exit }

disable-NetAdapterBinding -name "vEthernet (External Switch)" -ComponentID ms_server

enable-NetAdapterBinding -name "vEthernet (External Switch)" -ComponentID ms_server

Thank you so much @rpmurph83! I had to register to the forum just to thank you. I'm really glad you shared your findings.

I had a problem where my Hyper-V guests would not connect to my host file share. Restarting File and Printer Sharing For Microsoft Networks makes the guests to be able to connect to the file share. I think I've had this problem since 1809 or 1803.

I couldn't connect to port 445 via the ip address of my vEthernet (Default Switch) adapter using telnet. This fixes that problem, which seems to indicate Hyper-V guests are also able to connect.