How to Fix: Computer Name Won't Resolve on Network (April Update)

Infopackets Reader Steve J. writes:

" Dear Dennis,

Last week two of my systems (one a PC, the other a laptop) upgraded to Windows 10 version 1803, otherwise known as the 'April Creators Update' version of Windows 10. Ever since then, I can't access my laptop from my PC, though my PC can see the laptop. If I try and access either one directly, Windows 10 says it can't find the computer. Also my remote desktop protocol (RDP) no longer works. Researching 'network unc path april creators update broken' in Google reveals that this is an incredibly widespread issue. Can you please help? "

My response:

I asked Steve if he would like me to connect to his system using my remote desktop support service, and he agreed.

Understanding UNC Paths and IP Address Resolution

First, please be aware that when Windows won't resolve a computer name, it is still possible to access a system using an IP address directly providing the systems are on the same subnet and the Firewall allows it (which is in 99% of most cases where it worked before but no longer does).

For example, Steve's PC name is "Steves-PC" and his laptop name is "Laptop". When an UNC path (Universal Naming Convention path) resolves properly, typing in \\steves-pc into File Explorer will resolve the computer name to an IP address, and the same for any other machine on the network. Services such as Remote Desktop Protocol (RDP) use the same method to resolve computer names.

However, if the name resolution is broken, then things stop working. One way around this is to look at the IP address of each system and access it using the IP address. So, \\steves-pc might resolve to 192.168.0.5, which can be entered in as \\192.168.0.5 in File Explorer and Remote Desktop.

You can find out which IP is assigned to each PC by clicking Start, then type in "CMD";' wait for "CMD.EXE" or "Command Prompt" to appear, click it, then type in "ipconfig" and press Enter. The IP address of the computer will be revealed.

That said, this IP addresses in this manner is not convenient, and IP addresses on the network can change. But in an "emergency" situation when you just want it to work, an IP address is a quick way out.

Why UNC Paths Break with April Creators Update

The reason why the UNC paths won't resolve in Windows 10 April Creators Update is because Microsoft has removed "SMB v1.0" and "CIFS" services due to a critical bug that can allow for remote code execution. In other words, hackers could take over your system. This bug was discovered March 14, 2017 but it has taken Microsoft this long to issue a "fix," which unfortunately breaks the network name resolution for a lot of users.

It is possible to re-enable SMB v1.0 using Powershell, but due to the vulnerability I highly recommend you do not and instead follow the fix described next.

How to Fix: Computer Name Won't Resolve on Network (April Update)

Microsoft recommends setting a list of services on all your PCs as "Automatic (Delayed)" to help with the name resolution. In most cases this should resolve the issue, but in certain cases it may not work (such as with OpenVPN - I will describe a second method in a future post).

To do so:

1. Click Start, then type in "services.msc" and press Enter. The "Services" Window should now appear.
    
2. Scroll through the list of services, then double click "Function Discovery Provider Host (FDPHost)"; this will bring up a new window. Next to the heading "Service Status" it should say "Running"; if it is not, then click the "Start" button. Above that, set the "Startup type" to "Automatic (Delayed)".
    
3. Do the same for the following services: Function Discovery Resource Publication (FDResPub), Network Connections (NetMan), UPnP Device Host (UPnPHost), Peer Name Resolution Protocol (PNRPSvc), Peer Networking Grouping (P2PSvc), and Peer Networking Identity Manager (P2PIMSvc).
    
4. Repeat the same procedure for all PCs on the network.
    
5. When the changes have been made, reboot all PCs.
    
6. Finally, attempt to access your systems over the network using an UNC path using File Explorer.

In my testing, starting the first three services in the list: Function Discovery Provider Host (FDPHost), Function Discovery Resource Publication (FDResPub), and Network Connections (NetMan) made the Remote Desktop Protocol (RDP) and File Explorer resolve the computer names.

I hope that helps!

Additional 1-on-1 Support: From Dennis

If all of this is over your head, or if your networking name resolution is broken and you need help making it work again, I can help using my remote desktop support service. Simply contact me, briefly describing the issue and I will get back to you as soon as possible.

Got a Computer Question or Problem? Ask Dennis!

I need more computer questions. If you have a computer question -- or even a computer problem that needs fixing -- please email me with your question so that I can write more articles like this one. I can't promise I'll respond to all the messages I receive (depending on the volume), but I'll do my best.

About the author: Dennis Faas is the owner and operator of Infopackets.com. With over 30 years of computing experience, Dennis' areas of expertise are a broad range and include PC hardware, Microsoft Windows, Linux, network administration, and virtualization. Dennis holds a Bachelors degree in Computer Science (1999) and has authored 6 books on the topics of MS Windows and PC Security. If you like the advice you received on this page, please up-vote / Like this page and share it with friends. For technical support inquiries, Dennis can be reached via Live chat online this site using the Zopim Chat service (currently located at the bottom left of the screen); optionally, you can contact Dennis through the website contact form.