Forum Discussion
W10-1903 UNC path failing 0x80070043
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 0003SMB 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
Thanks for the clarification, I didn't catch the fine print of compression feature in 1903's SMB 3.1.1.
I really hope Microsoft and DELL can jointly work on this and come up with a fix soon.
Before a fix become available, I hope Microsoft can also provide some workaround solution like replacing the SMB dlls or some registry changes etc.
I personally have tried to replacing below DLLs from previous version of Windows 10 releases, but didn't work. Hope NedPyle can point out a better workaround solutions before we can get a permanent fix from DELL.
System32\ntshrui.dll
System32\smbwmiv2.dll
System32\SMBHelperClass.dll
SysWow64\SMBHelperClass.dll
System32\drivers\smbdirect.sys
IronRolia I've been telling users to rollback versions for now, as the Dell fix is to completely disable smb 3 on the NAS end. Not sure on what level you are dealing with the problem, but we've also blocked the 1903 rollout for now. I don't love the solution by any means, but just dealing with what we've got to work with.