Turn Off the hard disk (plugged in): registry value ACSettingIndexComputerHKLM\Software\Policies\Microsoft\Power\PowerSettings\6738E2C4-E8A5-4A42-B16A-E040E769756E

Policy ID: DiskACPowerDownTimeOut_2
Scope: Computer Configuration
Supported on: At least Windows Vista
Source: Administrative Templates (.admx) for Windows 11 2026 Update (26H2) (version 1.0)
Category: System › Power Management › Hard Disk Settings

Registry

ACSettingIndex

REG_DWORDComputer

HKLM\Software\Policies\Microsoft\Power\PowerSettings\6738E2C4-E8A5-4A42-B16A-E040E769756E Current key

Enabled value: Depends on the option value
Element: Turn Off the Hard Disk (seconds):
Value type: REG_DWORD
Required: true
Maximum value: 4294967295

Apply with .reg · CMD · PowerShell

.reg

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Power\PowerSettings\6738E2C4-E8A5-4A42-B16A-E040E769756E]

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

CMD

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

reg add "HKLM\Software\Policies\Microsoft\Power\PowerSettings\6738E2C4-E8A5-4A42-B16A-E040E769756E" /v "ACSettingIndex" /t REG_DWORD /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\Policies\Microsoft\Power\PowerSettings\6738E2C4-E8A5-4A42-B16A-E040E769756E' -Force | Out-Null
New-ItemProperty -Path 'HKLM:\Software\Policies\Microsoft\Power\PowerSettings\6738E2C4-E8A5-4A42-B16A-E040E769756E' -Name 'ACSettingIndex' -PropertyType DWord -Value '<enter value>' -Force | Out-Null