Deny write access to fixed drives not protected by BitLocker: registry value FDVDenyWriteAccessComputerHKLM\System\CurrentControlSet\Policies\Microsoft\FVE

Policy ID: FDVDenyWriteAccess_Name
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: Windows Components › BitLocker Drive Encryption › Fixed Data Drives

Registry

FDVDenyWriteAccess

REG_DWORDComputer

HKLM\System\CurrentControlSet\Policies\Microsoft\FVE Current key

Enabled value: 1
Disabled value: 0

Apply with .reg · CMD · PowerShell

.reg

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\System\CurrentControlSet\Policies\Microsoft\FVE]

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

CMD

:: Options (use only one)

:: Enabled
reg add "HKLM\System\CurrentControlSet\Policies\Microsoft\FVE" /v "FDVDenyWriteAccess" /t REG_DWORD /d 1 /f
:: Disabled
reg add "HKLM\System\CurrentControlSet\Policies\Microsoft\FVE" /v "FDVDenyWriteAccess" /t REG_DWORD /d 0 /f

PowerShell

# Common: create the key
New-Item -Path 'HKLM:\System\CurrentControlSet\Policies\Microsoft\FVE' -Force | Out-Null

# Options (use only one)
# Enabled
New-ItemProperty -Path 'HKLM:\System\CurrentControlSet\Policies\Microsoft\FVE' -Name 'FDVDenyWriteAccess' -PropertyType DWord -Value 1 -Force | Out-Null
# Disabled
New-ItemProperty -Path 'HKLM:\System\CurrentControlSet\Policies\Microsoft\FVE' -Name 'FDVDenyWriteAccess' -PropertyType DWord -Value 0 -Force | Out-Null