Windows (10 & 2016) Build 1709 & 1803 cannot connect to SMB Shares

Applies to: Windows 10, version 1803, Windows Server version 1803, Windows 10, version 1709, Windows Server Datacenter Core, and Windows Server Standard Core

As users and organizations are upgrading to Windows 10 Build 1709/1803 they should be aware that SMB 1.0 is no longer installed by default. Among other things, this is going to start a lot of problems especially for the networking and security departments where they might be trying to figure out if it is a firewall that is blocking or an AV program that is limiting the access to the share.

In Windows 10 Fall Creators Update (1709), and Windows Server, version 1709 (RS3) and later versions, the Server Message Block version 1 (SMBv1) network protocol is no longer installed by default. It was superseded by SMBv2 and later protocols starting in 2007. Microsoft publicly deprecated the SMBv1 protocol in 2014.

SMBv1 has the following behavior in Windows 10 Fall Creators Update and Windows Server, version 1709 (RS3):

  • SMBv1 now has both client and server sub-features that can be uninstalled separately.
  • Windows 10 Enterprise and Windows 10 Education no longer contain the SMBv1 client or server by default after a clean installation.
  • Windows Server 2016 no longer contains the SMBv1 client or server by default after a clean installation.
  • Windows 10 Home and Windows 10 Professional no longer contain the SMBv1 server by default after a clean installation.
  • Windows 10 Home and Windows 10 Professional still contain the SMBv1 client by default after a clean installation. If the SMBv1 client is not used for 15 days in total (excluding the computer being turned off), it automatically uninstalls itself.
  • In-place upgrades and Insider flights of Windows 10 Home and Windows 10 Professional do not automatically remove SMB1 initially. If the SMBv1 client or server is not used for 15 days in total (excluding the time during which the computer is off), they each automatically uninstall themselves.
  • In-place upgrades and Insider flights of Windows 10 Enterprise and Windows 10 Education do not automatically remove SMB1. An administrator must decide to uninstall SMB1 in these managed environments.
  • Automatic removal of SMB1 after 15 days is a one-time operation. If an administrator re-installs SMB1, no further attempts will be made to uninstall it.
  • The SMB version 2.02, 2.1, 3.0, 3.02, and 3.1.1 features are still fully supported and included by default as part of the SMBv2 binaries.
  • Because the Computer Browser service relies on SMBv1, the service is uninstalled if the SMBv1 client or server is uninstalled. This means that Explorer Network can no longer display Windows computers through the legacy NetBIOS datagram browsing method.
  • SMBv1 can still be reinstalled in all editions of Windows 10 and Windows Server 2016.

If you try to connect to devices that support only SMBv1, or if these devices try to connect to you, you may receive one of the following errors messages:

You can’t connect to the file share because it’s not secure. This share requires the obsolete SMB1 protocol, which is unsafe and could expose your system to attack. Your system requires SMB2 or higher. For more info on resolving this issue, see: https://go.microsoft.com/fwlink/?linkid=852747