What is SMB? How to disable SMB3 in Windows 10

What is SMB?

Server Message Block, or SMB, is an application-layer network protocol, developed primarily by Microsoft for general access to files, serial ports, and various communications between network nodes. It allows computer applications to read and write to files as well as service requests from server programs on the computer network.

The SMB2 and / or SMB3 protocols are enabled by default in Windows.

Note: SMB2 and SMB3 are linked to each other. So enabling or disabling SMB2 will result in the same thing for SMB3.

Follow 2 methods bellow to disable SMB3 in Windows 10

Disable SMB3 with PowerShell (recommended)

1. Open PowerShell with admin permission .

2. Verify that SMB3 is enabled by executing the command below. If the protocol is enabled, you will see “true” in the response.

Get-SmbServerConfiguration | Select EnableSMB2Protocol

3. To turn off SMB3, execute this command :

Set-SmbServerConfiguration -EnableSMB2Protocol $ false

4. PowerShell will ask for your confirmation, type Y or A and press Enter to confirm.

5. When disabled, you can verify it by executing the first command in Steps 2. If the protocol is disabled, you will see “false”.


6. Finally, restart your Windows to apply the changes.

To reactivate SMB3, you can use the command below.

Set-SmbServerConfiguration -EnableSMB2Protocol $true

Disable SMB3 with Command Prompt

You also can use the Command Prompt to disable SMB3.

1. Run Command Prompt with admin permission .

2. In the Command Prompt window, execute the following commands one after the other.

sc.exe config lanmanworkstation depend = bowser / mrxsmb10 / nsi
sc.exe config mrxsmb20 start = disabled

3. When done, restart your Windows to apply the changes. After reboot, the SMB3 protocol will be disabled.

To re-enable the SMB3 protocol, open the Command Prompt with admin permission  and execute the following commands one after the other.

sc.exe config lanmanworkstation depend = bowser / mrxsmb10 / mrxsmb20 / nsi
sc.exe config mrxsmb20 start = auto