Use forest search order: registry value UseForestSearch and 1 more (KDC\Parameters)ComputerHKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\KDC\Parameters

Policy ID: ForestSearch
Scope: Computer Configuration
Supported on: At least Windows Server 2008 R2 or Windows 7
Source: Administrative Templates (.admx) for Windows 11 2026 Update (26H2) (version 1.0)
Category: System › KDC

Registry

UseForestSearch

REG_DWORDComputer

HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\KDC\Parameters Current key

Enabled value: 1
Disabled value: 0

Apply with .reg · CMD · PowerShell

.reg

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System\KDC\Parameters]

; Options (use only one)
; Enabled
"UseForestSearch"=dword:00000001
; Disabled
"UseForestSearch"=dword:00000000

CMD

:: Options (use only one)

:: Enabled
reg add "HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\KDC\Parameters" /v "UseForestSearch" /t REG_DWORD /d 1 /f
:: Disabled
reg add "HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\KDC\Parameters" /v "UseForestSearch" /t REG_DWORD /d 0 /f

PowerShell

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

# Options (use only one)
# Enabled
New-ItemProperty -Path 'HKLM:\Software\Microsoft\Windows\CurrentVersion\Policies\System\KDC\Parameters' -Name 'UseForestSearch' -PropertyType DWord -Value 1 -Force | Out-Null
# Disabled
New-ItemProperty -Path 'HKLM:\Software\Microsoft\Windows\CurrentVersion\Policies\System\KDC\Parameters' -Name 'UseForestSearch' -PropertyType DWord -Value 0 -Force | Out-Null

ForestSearchList

REG_SZComputer

HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\KDC\Parameters Current key

Enabled value: Depends on the option value
Element: Forests to Search
Value type: REG_SZ
Required: true

Apply with .reg · CMD · PowerShell

.reg

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System\KDC\Parameters]

; Value names and types follow the ADMX. Replace <enter value> below with your own data
"ForestSearchList"="<enter value>"

CMD

:: Value names and types follow the ADMX. Replace <enter value> below with your own data

reg add "HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\KDC\Parameters" /v "ForestSearchList" /t REG_SZ /d "<enter value>" /f

PowerShell

# Value names and types follow the ADMX. Replace <enter value> below with your own data

New-Item -Path 'HKLM:\Software\Microsoft\Windows\CurrentVersion\Policies\System\KDC\Parameters' -Force | Out-Null
New-ItemProperty -Path 'HKLM:\Software\Microsoft\Windows\CurrentVersion\Policies\System\KDC\Parameters' -Name 'ForestSearchList' -PropertyType String -Value '<enter value>' -Force | Out-Null