W10-1903 UNC path failing 0x80070043

I can no longer access network shares through unc paths \\server\share I get the 0x80070043 "Network name cannot be found" error. I suspect that this is related to the removal of Homegroups? but ...

NedPyle
Jun 13, 2019
Hi everyone. We got access to the Dell KB and see the issue in Dell/EMCs 'Unity' CIFS implementation.

From the DELL EMC KB attached to thread (below), the Unity SMB Server implementation is failing on the "SMB2_NETNAME_CONTEXT" and "SMB2_COMPRESSION_CAPABILITIES" we added in 1903. These were changes designed to add some new capabilities to SMB; we make some variant of these at most OS releases. If an SMB/CIFS server doesn't recognize capabilities, it should ignore them, not fail. Otherwise Dell would have to update their SMB implementation every time we released a new SMB capability that didn't also include a protocol dialect revision (like "SMB 3.1.2"), forever and ever.

Error Messages in the Unity c4_safe_ktrace.log:

sade:SMB: 3:[nas_serverx] Unrecognized SMB2 negotiate context type 0003
sade:SMB: 3:[nas_serverx] Unrecognized SMB2 negotiate context type 0003

SMB client sends the compression context before the netname context, so the server encounters the compression context first. The Unity server would probably encounter the same problem with the netname context. Instead of failing when their SMB Server version doesn't support more advanced capabilities, it should be ignoring those capabilities. This is what Windows and other 3rd party SMB products do.

kurgan thanks for opening this techcommunity item, I'm sorry I didn't see it until now.

Ned Pyle | Principal Program Manager, MS | @nerdpyle on twitter

Rohit_Sakhrani

Copper Contributor

Apr 16, 2019

Make sure they are connected on the same network. In network sharing settings, enable 128 Bit encryption and allow network discovery. There are 7 services related to network sharing in services.msc. Also, both systems must run on the same build of Windows 10.

Joe Wright
Copper Contributor
Apr 16, 2019
Rohit_Sakhrani

I think you're missing a part of this. We're talking about a DELL EMC box not running Windows. It's running Linux but SMB has worked without issue on all prior Windows 10 versions. Things broke with 1903
- k_perri
  Copper Contributor
  Apr 24, 2019
  Just downloaded and installed the Windows 10 Enterprise 1903 release from MSDN to test and this issue is still present. On latest build 18362.53. Our company's files shares are mostly hosted from Dell EMC/Unity. I have been able to confirm that Windows Server file shares and Nutanix Files shares are unaffected. Hopefully they will get this fixed by the RTM next month.
  - itkpli
    Brass Contributor
    Apr 25, 2019
    k_perri
    Just wanted to add that we also have problems using SMB with 1903 and our 2 Unity 400 (latest code).
    
    This is a big issue for us but I find it strange that I haven't found anything on the Internet about this except here.

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W10-1903 UNC path failing 0x80070043

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