Deny write access to fixed drives not protected by BitLocker
Verified with Windows 11 25H2 — updated on July 10, 2026
Supported on: At least Windows Server 2008 R2 or Windows 7
Path in the GPO console
Computer Configuration\Administrative Templates\Windows Components\BitLocker Drive Encryption\Fixed Data Drives Description
This policy setting determines whether BitLocker protection is required for fixed data drives to be writable on a computer. If you enable this policy setting, all fixed data drives that are not BitLocker-protected will be mounted as read-only. If the drive is protected by BitLocker, it will be mounted with read and write access. If you disable or do not configure this policy setting, all fixed data drives on the computer will be mounted with read and write access.
Registry
HKLM
System\CurrentControlSet\Policies\Microsoft\FVE Value name: FDVDenyWriteAccess
Enabled: FDVDenyWriteAccess = 1
Disabled: FDVDenyWriteAccess = 0
Export Builder
BETAConfigure the state, scope and options, then generate .reg, PowerShell, Intune and SCCM outputs — or add the setting to a multi-setting collection.
These exports write the registry — this is not a managed GPO. ⓘ
.reg file
Windows Registry Editor Version 5.00
; Exported from gporais.com
; Policy: Deny write access to fixed drives not protected by BitLocker
; State: Enabled
; Supported on: At least Windows Server 2008 R2 or Windows 7
[HKEY_LOCAL_MACHINE\System\CurrentControlSet\Policies\Microsoft\FVE]
"FDVDenyWriteAccess"=dword:00000001More formats (PowerShell, Intune, SCCM)
PowerShell
# Exported from gporais.com
# Policy: Deny write access to fixed drives not protected by BitLocker
# State: Enabled
# Supported on: At least Windows Server 2008 R2 or Windows 7
$path = 'HKLM:\System\CurrentControlSet\Policies\Microsoft\FVE'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'FDVDenyWriteAccess' -Value 1 -Type DWordIntune XML
No direct Policy CSP / OMA-URI mapping for this policy. Use the Intune Remediation tab, or ingest the ADMX in Intune.Intune Remediation
# === Detection script ===
# Exported from gporais.com
# Policy: Deny write access to fixed drives not protected by BitLocker
# State: Enabled
# Supported on: At least Windows Server 2008 R2 or Windows 7
function Test-RegistryValue {
param(
[Parameter(Mandatory = $true)][string]$Path,
[Parameter(Mandatory = $true)][string]$Name,
[object]$Expected,
[ValidateSet('String', 'DWord', 'MultiString')][string]$Kind = 'String',
[switch]$Absent
)
try {
$item = Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction Stop
} catch {
return $Absent.IsPresent
}
if ($Absent.IsPresent) { return $false }
$actual = $item.$Name
if ($Kind -eq 'DWord') { return ([int64]$actual) -eq ([int64]$Expected) }
if ($Kind -eq 'MultiString') {
$actualValues = @($actual)
$expectedValues = @($Expected)
if ($actualValues.Count -ne $expectedValues.Count) { return $false }
for ($i = 0; $i -lt $expectedValues.Count; $i++) {
if ([string]$actualValues[$i] -ne [string]$expectedValues[$i]) { return $false }
}
return $true
}
return [string]$actual -eq [string]$Expected
}
$checks = @(
(Test-RegistryValue -Path 'HKLM:\System\CurrentControlSet\Policies\Microsoft\FVE' -Name 'FDVDenyWriteAccess' -Expected 1 -Kind DWord)
)
if ($checks -notcontains $false) {
Write-Output 'Compliant'
exit 0
}
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Deny write access to fixed drives not protected by BitLocker
# State: Enabled
# Supported on: At least Windows Server 2008 R2 or Windows 7
$path = 'HKLM:\System\CurrentControlSet\Policies\Microsoft\FVE'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'FDVDenyWriteAccess' -Value 1 -Type DWordSCCM scripts
# Exported from gporais.com
# Policy: Deny write access to fixed drives not protected by BitLocker
# State: Enabled
# Supported on: At least Windows Server 2008 R2 or Windows 7
# SCCM Configuration Item guidance:
# Create a Configuration Item of type "Setting: Script".
# Discovery script: use the Detection script below.
# Remediation script: use the Remediation script below.
# Compliance rule: the Discovery script output equals 'Compliant'.
# === Detection script ===
# Exported from gporais.com
# Policy: Deny write access to fixed drives not protected by BitLocker
# State: Enabled
# Supported on: At least Windows Server 2008 R2 or Windows 7
function Test-RegistryValue {
param(
[Parameter(Mandatory = $true)][string]$Path,
[Parameter(Mandatory = $true)][string]$Name,
[object]$Expected,
[ValidateSet('String', 'DWord', 'MultiString')][string]$Kind = 'String',
[switch]$Absent
)
try {
$item = Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction Stop
} catch {
return $Absent.IsPresent
}
if ($Absent.IsPresent) { return $false }
$actual = $item.$Name
if ($Kind -eq 'DWord') { return ([int64]$actual) -eq ([int64]$Expected) }
if ($Kind -eq 'MultiString') {
$actualValues = @($actual)
$expectedValues = @($Expected)
if ($actualValues.Count -ne $expectedValues.Count) { return $false }
for ($i = 0; $i -lt $expectedValues.Count; $i++) {
if ([string]$actualValues[$i] -ne [string]$expectedValues[$i]) { return $false }
}
return $true
}
return [string]$actual -eq [string]$Expected
}
$checks = @(
(Test-RegistryValue -Path 'HKLM:\System\CurrentControlSet\Policies\Microsoft\FVE' -Name 'FDVDenyWriteAccess' -Expected 1 -Kind DWord)
)
if ($checks -notcontains $false) {
Write-Output 'Compliant'
exit 0
}
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Deny write access to fixed drives not protected by BitLocker
# State: Enabled
# Supported on: At least Windows Server 2008 R2 or Windows 7
$path = 'HKLM:\System\CurrentControlSet\Policies\Microsoft\FVE'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'FDVDenyWriteAccess' -Value 1 -Type DWordBuilding a multi-setting collection? Add this setting and generate combined .reg / PowerShell / GPO scripts.