Windows 10 error with VPNs

[HCHTech]

I have a customer with a Synology NAS and a Sonicwall TZ300. They have 4 remote workers that use the Sonicwall SSL VPN client to access the company files on the NAS. All computers are running Windows 10 Pro. In the last week or so (maybe post-anniversary update), everyone has been getting intermittent errors when transferring files across the VPN.

"Error 0x8007003B: An unexpected network error occurred."

This is apparently a bug in Windows 10. specifically when using SMB version 2 or 3 over a VPN.

The workaround, until such time as Microsoft fixes the problem, is to restrict the computers to using only SMB version 1. This can be accomplished by running the following command from an elevated command prompt:

sc.exe config lanmanworkstation depend= bowser/mrxsmb10/nsi
sc.exe config mrxsmb20 start= disabled

then rebooting.

In case this doesn't work or causes other problems, these settings can be returned to normal with the following commands:

sc.exe config lanmanworkstation depend= bowser/mrxsmb10/mrxsmb20/nsi
sc.exe config mrxsmb20 start= auto

Anyway, this fix worked for my customer - I hope it saves someone else some time.

 

[Merlin Halteman]

Interesting observation! I know we have found this to be an issue post Win 10 Anniversary update. https://social.technet.microsoft.co...rsary-update-error?forum=win10itpronetworking

I don't know if it is related but I think it could be. Thanks

 

[HCHTech]

And.......it's back. the problems have returned even though no new updates were loaded. As a test, I've rolled one computer back to 8/1 - uninstalled all updates loaded since then, unwound the SMB changes I made above, and set their ethernet connection to metered with a registry change to prevent any future updates for a while. We'll see.