Sometimes security is on the border of being ridiculous. Modern Windows 10 is very anxious when connecting to guest-access allowed, readonly Samba shares, Here’s how to allow “insecure” guest logons for stand-alone computers. The same is true when configuring a GPO. https://support.microsoft.com/en-us/help/4046019/guest-access-smb2-disabled-by-default-in-windows-10-server-2016.

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