After installing a Windows 10 update on my PC, I can no longer connect to it from Mavericks...

[Wowfunhappy]

So this has been bugging me for a while, but I'm pretty clueless as to what's wrong.

I have a PC I use for video games, which runs Windows 10 LTSC 1809. I have Windows 10's native file sharing enabled, which I used to be able to connect to from my Mac running Mavericks.

At some point in the fall (I don't remember exactly when, which is frustrating!) I installed a bunch of security updates. The nice thing about LTSC versions of Windows is that they only ever get security updates, which usually means nothing breaks. Unfortunately, since this update, I've been unable to connect to the PC's SMB share from my 10.9 Mac. If I select it in the Finder Sidebar, it just says "Connection Failed". If I use Go → Connect to Server... → smb://[my PC's IP Address]/[Share], I am able to enter my credentials, but am eventually told:

Notably, it isn't rejecting my password. I don't get this message if I input the wrong credentials. Also, the process works fine in reverse—the PC has no trouble connecting to my Mac via SMB.

I'm a little stumped here. I don't know a lot about how SMB works on the Windows side, and I can't figure out what could have changed in that Windows 10 update, whatever it was. Anyone have a clue what might be happening?

 

[MysticCow]

What happens if you try the reverse and connect your PC to the Mac? Just curious and it might give information needed.

 

[eyoungren]

I had something similar happen to be about a year or so ago. In order to connect I had to add the guest account to all shared resources and assign the guest account admin sharing rights.

Connecting also required the guest account not to use a password. If I tried to use one or my regular account credentials the connection failed.

Later on another update seemed to fix that. But it was irritating for a while. Ultimately I rolled back to Windows 7.

 

[Wowfunhappy]

What happens if you try the reverse and connect your PC to the Mac? Just curious and it might give information needed.

As noted, it works perfectly.

I had something similar happen to be about a year or so ago. In order to connect I had to add the guest account to all shared resources and assign the guest account admin sharing rights.

Interesting. Something to try I guess!

Edit: Nope.

 

[eyoungren]

Interesting. Something to try I guess!

Edit: Nope.

Maybe try using CIFS instead of SMB? Might be worth a shot.

 

[Wowfunhappy]

Maybe try using CIFS instead of SMB? Might be worth a shot.

That was a good idea, which I'm not sure why I hadn't tried before. Initially it couldn't connect at all, but then I remembered Windows disables SMB 1 support by default nowadays. I went into Windows 10's Control Panel and enabled it.

That allowed the Mac to pop up a login prompt... but it ultimately errors out the same way as standard SMB. ?

I'm convinced that Microsoft added some sort of vulnerability fix which is breaking things, since this version of Windows is only ever supposed to get security updates. But I have no idea what that would be or how it could be switched off...

 

[Wowfunhappy]

This is mildly interesting:

My 10.6 and 10.7 VMs are able to connect to the PC.
My 10.8 and 10.9 VMs are unable to connect.
My 10.13 VM is able to connect.

(Nothing in OS X's Console, btw. Would have included that if there was.)

 

[Wowfunhappy]

Wat. I actually fixed it.

sudo sh -c "echo '[default]' >> /etc/nsmb.conf; echo 'signing_required=yes' >> /etc/nsmb.conf"

I'd, uh, love to know what this actually does! "Signing required" is the type of security setting you'd expect to break compatibility, not fix it...

 

[eyoungren]

Wat. I actually fixed it.

sudo sh -c "echo '[default]' >> /etc/nsmb.conf; echo 'signing_required=yes' >> /etc/nsmb.conf"

I'd, uh, love to know what this actually does! "Signing required" is the type of security setting you'd expect to break compatibility, not fix it...

Ah, yes. You can also go the other way and disable signing in the registry of the Windows machine.

 

[Wowfunhappy]

Ah, yes. You can also go the other way and disable signing in the registry of the Windows machine.

Do you happen to know what this setting is? Is there a configuration that will make the Mac compatible with both types of servers?