Configure server authentication for client: registry value AuthenticationLevelComputerHKLM\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services

Policy ID: TS_SERVER_AUTH
Scope: Computer Configuration
Supported on: At least Windows Vista with Service Pack 1
Source: Administrative Templates (.admx) for Windows 11 2026 Update (26H2) (version 1.0)
Category: Windows Components › Remote Desktop Services › Remote Desktop Connection Client

Registry

AuthenticationLevel

REG_DWORDComputer

HKLM\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services Current key

Enabled value: Depends on the option value
Element: Authentication setting:

Options
Item	Stored value
Always connect, even if authentication fails	0
Warn me if authentication fails	2
Do not connect if authentication fails	1

Apply with .reg · CMD · PowerShell

.reg

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services]

; Options (use only one)
; Always connect, even if authentication fails
"AuthenticationLevel"=dword:00000000
; Warn me if authentication fails
"AuthenticationLevel"=dword:00000002
; Do not connect if authentication fails
"AuthenticationLevel"=dword:00000001

CMD

:: Options (use only one)

:: Always connect, even if authentication fails
reg add "HKLM\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services" /v "AuthenticationLevel" /t REG_DWORD /d 0 /f
:: Warn me if authentication fails
reg add "HKLM\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services" /v "AuthenticationLevel" /t REG_DWORD /d 2 /f
:: Do not connect if authentication fails
reg add "HKLM\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services" /v "AuthenticationLevel" /t REG_DWORD /d 1 /f

PowerShell

# Common: create the key
New-Item -Path 'HKLM:\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services' -Force | Out-Null

# Options (use only one)
# Always connect, even if authentication fails
New-ItemProperty -Path 'HKLM:\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services' -Name 'AuthenticationLevel' -PropertyType DWord -Value 0 -Force | Out-Null
# Warn me if authentication fails
New-ItemProperty -Path 'HKLM:\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services' -Name 'AuthenticationLevel' -PropertyType DWord -Value 2 -Force | Out-Null
# Do not connect if authentication fails
New-ItemProperty -Path 'HKLM:\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services' -Name 'AuthenticationLevel' -PropertyType DWord -Value 1 -Force | Out-Null