How to Disable SMBv1 and Have SMBv3 Take Over?

hrussd · 05 May 2018

My small LAN consists of only 2 PCs, my desktop and my notebook, both running Windows 10 Home. There are also various Apple devices, an Amazon device, some home security devices, and an ASUS RT-N56U router.

Three days ago, I installed Windows 10 version 1803 on both PCs. Things were fine until yesterday, when my daily backup from my desktop to the notebook hard drive failed. Investigation of my desktop revealed that none of the three computers (Windows counts the router as a computer) were appearing under Network in File Explorer; in fact, the Computer category was not even displayed there. However, on the notebook, the computer category was displayed in File Explorer, and all three computers were displayed there. I was able to access folders and files in the desktop from the notebook. I ran my IPScanner (from the desktop), and everything looked OK with all devices responding.

After some browsing on the Internet, I found a suggestion that the problem could be caused because SMBv1 was disabled. Using Windows Features in Control Panel, I found that all three entries under "SMB 1.0/CIFS File Sharing Support" where indeed disabled (unchecked). I checked the later two boxes ("SMB 1.0/CIFS Client" and "SMB 1.0/CIFS Server"). After rebooting, my LAN worked properly again! I don't know (or much care) how SMBv1 got disabled on my desktop (but not on my notebook).

Now subsequent browsing has caused me to discover that SMBv1 has long ago been deprecated by Microsoft, and that it has major security issues and indeed should be disabled. My reading indicates that after disabling SMBv1, SMBv3 (or possibly SMBv2) should have kept my LAN working. That did not happen.

Now I am in a quandary: give up my LAN and my daily backup, or continue using SMBv1. If anyone can tell me how to get SMBv3 to take over after disabling SMBv1, I would be most grateful!

Also, does anyone know if my Norton Security (which informs me it is up to date) is offering any protection from the SMBv1 vulnerability?

Access Denied · 05 May 2018

You do not need SMBv1. Go back to where you enabled it and disable it.

Enable or Disable SMB1 File Sharing Protocol in Windows | Windows 10 Tutorials

Then you can fix your network showing in 1803 with these steps:

You need to set two services to automatic (delayed start):

Function Discovery Provider Host
Function Discovery Resource Publication

Open a Run box, (win key + R) type services.msc and press enter to open the Services List. Scroll down until you find those two. Set them to automatic (delayed start). Then right click and start them both. That PC will now show up.

These two services should run automatically but for some reason they are not in 1803. This has been checked in 1709 and other versions. For some reason they are not running in 1803 but setting them as above will fix the issue of the network showing for you.

hrussd · 05 May 2018

"Access Denied": Thanks for your incredibly quick and spot-on reply! I followed your suggested steps on each PC, and now all seems well.

Two followups:

Why Delayed start, vs. just Automatic?

On both PCs, File Explorer shows just the two PCs under the "Computer" category. The router is now shown under a new (to me) category: "Network Infrastructure". This seems fitting and proper. Is that the way it should be?

Access Denied · 05 May 2018

I said delayed start so they won't be trying to run as soon as you boot your computer. Some need all the power they can get to boot up and any added things might slow it down. I do not see any reason to keep them on delayed if you want to run them automatically at boot.

Yes the router will show depending on the router. This is normal.

You are very welcome. Glad I could be of help. :)

tracit99 · 06 May 2018

I have always set the two services to Automatic which fixes several Networking issues. The issue that I have is that my Asus router only supports SMB1 and therefore if I want to see my router share in Network I have to enable SMB1 on my computer(s). Yes I am aware that this a known security risk but it is one that I am willing to take. Many routers and NAS devices only support SMB1 presently and one has to choose their poison. Hopefully router and NAS device manufactures will update their firmware soon.