Sunday, March 15, 2015

Resolving Mini WAN Miniport Code 31 Errors on Windows 8.1

After a recent Windows update I could no longer connect to one of my VPNs using the native Windows VPN connectivity (i.e. not a client like Cisco AnyConnect). When I tried to connect from the networking charm (I think that's what they call the bar on the right-hand side of the screen) it would hang for a while but never connect, and after that happened when I clicked on the networking icon on the lower right the charm bar wouldn't even come back.

I figured it might be a driver issue so I opened up Device Manager and sure enough, under the network adapters section there were yellow exclamation marks next to every one of the WAN Miniports that show up after you try to connect to a VPN.

I found varying reports of how to fix the problem but here's what worked for me.

  1. Try to connect to a VPN that will cause things to error out (the WAN Miniports didn't even show up in the network adapter list for me until I did this)
  2. Open Device Manager
  3. Expand "Network adapters"
  4. Right-click every one of the WAN Miniport devices (I even did the ones that didn't have a yellow exclamation point next to them) and do the following:
    1. Click "Update Driver Software"
    2. Click "Browse my computer for driver software"
    3. Click "Let me pick from a list of device drivers on my computer"
    4. Uncheck the "Show compatible hardware" box
    5. Under Manufacturer choose Microsoft
    6. Under Network Adapter choose "Microsoft KM-Test Loopback Adapter" (technically from what I understand you can pick anything that you can uninstall, but this one worked consistently for me)
    7. Click "Next"
    8. Ignore the "blah blah might be incompatbile" warning and click OK
    9. After Device Manager refreshes, right click the Microsoft KM-Test Loopback Adapter and click "Uninstall"
  5. After you've done that for every one of the WAN Miniports listed, reboot the machine. If you don't do this things won't be fixed.
That cleaned things up for me. We'll see if it works on subsequent reboots.


Pasha MESH said...

Thank you. Your instructions helps me to solve VPN PPTP connection issue.

It's works even without reboot.

Thomas said...

You are my personal hero and you really saved my day! Thanks for your tutorial.

My Network settings / Share center was freezing for 5–10 minutes everytime I opened it. I lived with this for quite some time, but now I needed to use vagrant / homestead and it would hang as well, because it tries to set network connections at some time.

When I fixed the WLAN Miniport issues, everything worked again.

One hint: You should really really do this for ALL WLAN Miniport entries. If after reboot it doesn't work, do it again for the entries that didn't work.

I finally succeeded with this absurd workaround after a long time of research and approximately one million reboots today. Just another reason to finally get rid of my windows partition.