Mandate the maximum version of SMB: registry value MaxSmb2Dialect (LanmanWorkstation)ComputerHKLM\Software\Policies\Microsoft\Windows\LanmanWorkstation

Policy ID: Pol_MaxSmb2Dialect
Scope: Computer Configuration
Supported on: At least Windows Server 2025, Windows 11
Source: Administrative Templates (.admx) for Windows 11 2026 Update (26H2) (version 1.0)
Category: Network › Lanman Workstation

Registry

MaxSmb2Dialect

REG_DWORDComputer

HKLM\Software\Policies\Microsoft\Windows\LanmanWorkstation Current key

Enabled value: Depends on the option value
Element: Version:

Options
Item	Stored value
SMB 3.1.1	785
SMB 3.0.2	770
SMB 3.0.0	768
SMB 2.1.0	528
SMB 2.0.2	514

Apply with .reg · CMD · PowerShell

.reg

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\LanmanWorkstation]

; Options (use only one)
; SMB 3.1.1
"MaxSmb2Dialect"=dword:00000311
; SMB 3.0.2
"MaxSmb2Dialect"=dword:00000302
; SMB 3.0.0
"MaxSmb2Dialect"=dword:00000300
; SMB 2.1.0
"MaxSmb2Dialect"=dword:00000210
; SMB 2.0.2
"MaxSmb2Dialect"=dword:00000202

CMD

:: Options (use only one)

:: SMB 3.1.1
reg add "HKLM\Software\Policies\Microsoft\Windows\LanmanWorkstation" /v "MaxSmb2Dialect" /t REG_DWORD /d 785 /f
:: SMB 3.0.2
reg add "HKLM\Software\Policies\Microsoft\Windows\LanmanWorkstation" /v "MaxSmb2Dialect" /t REG_DWORD /d 770 /f
:: SMB 3.0.0
reg add "HKLM\Software\Policies\Microsoft\Windows\LanmanWorkstation" /v "MaxSmb2Dialect" /t REG_DWORD /d 768 /f
:: SMB 2.1.0
reg add "HKLM\Software\Policies\Microsoft\Windows\LanmanWorkstation" /v "MaxSmb2Dialect" /t REG_DWORD /d 528 /f
:: SMB 2.0.2
reg add "HKLM\Software\Policies\Microsoft\Windows\LanmanWorkstation" /v "MaxSmb2Dialect" /t REG_DWORD /d 514 /f

PowerShell

# Common: create the key
New-Item -Path 'HKLM:\Software\Policies\Microsoft\Windows\LanmanWorkstation' -Force | Out-Null

# Options (use only one)
# SMB 3.1.1
New-ItemProperty -Path 'HKLM:\Software\Policies\Microsoft\Windows\LanmanWorkstation' -Name 'MaxSmb2Dialect' -PropertyType DWord -Value 785 -Force | Out-Null
# SMB 3.0.2
New-ItemProperty -Path 'HKLM:\Software\Policies\Microsoft\Windows\LanmanWorkstation' -Name 'MaxSmb2Dialect' -PropertyType DWord -Value 770 -Force | Out-Null
# SMB 3.0.0
New-ItemProperty -Path 'HKLM:\Software\Policies\Microsoft\Windows\LanmanWorkstation' -Name 'MaxSmb2Dialect' -PropertyType DWord -Value 768 -Force | Out-Null
# SMB 2.1.0
New-ItemProperty -Path 'HKLM:\Software\Policies\Microsoft\Windows\LanmanWorkstation' -Name 'MaxSmb2Dialect' -PropertyType DWord -Value 528 -Force | Out-Null
# SMB 2.0.2
New-ItemProperty -Path 'HKLM:\Software\Policies\Microsoft\Windows\LanmanWorkstation' -Name 'MaxSmb2Dialect' -PropertyType DWord -Value 514 -Force | Out-Null