Control use of the File System API for writing

Computer and userIntune-readyDefaultFileSystemWriteGuardSetting

Supported on Microsoft Edge version 86, Windows 7 or later

155.0.4283.62

What it does

If you set this policy to 3, websites can ask for write access to the host operating system's filesystem using the File System API. If you set this policy to 2, access is denied. If you don't set this policy, websites can ask for access. Users can change this setting. Policy options mapping: * BlockFileSystemWrite (2) = Don't allow any site to request write access to files and directories * AskFileSystemWrite (3) = Allow sites to ask the user to grant write access to files and directories Use the preceding information when configuring this policy.

What it writes

Hive: HKEY_LOCAL_MACHINE or HKEY_CURRENT_USER
Registry key: Software\Policies\Microsoft\Edge

Options

Option	Type	Registry value	Allowed values
Control use of the File System API for writing	Drop-down list	`DefaultFileSystemWriteGuardSetting`	Don't allow any site to request write access to files and directories`2` Allow sites to ask the user to grant write access to files and directories`3`

Configure and deploy

Choose a state and the option values; the output below is generated from the template for exactly that.

Enabled · Computer · template defaults

Registry file (.reg)

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Edge]
"DefaultFileSystemWriteGuardSetting"=dword:00000002

PowerShell

$ErrorActionPreference = 'Stop'

function Set-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $PropertyType,
        [Parameter(Mandatory = $true)][object] $Value
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        New-Item -Path $Path -Force | Out-Null
    }

    New-ItemProperty -LiteralPath $Path -Name $Name -PropertyType $PropertyType -Value $Value -Force | Out-Null
}

function Remove-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (Test-Path -LiteralPath $Path) {
        Remove-ItemProperty -LiteralPath $Path -Name $Name -Force -ErrorAction SilentlyContinue
    }
}

function Clear-RegistryKeyValues {
    param(
        [Parameter(Mandatory = $true)][string] $Path
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return
    }

    foreach ($propertyName in (Get-Item -LiteralPath $Path).Property) {
        Remove-ItemProperty -LiteralPath $Path -Name $propertyName -Force -ErrorAction SilentlyContinue
    }
}

# Policy: Control use of the File System API for writing
# Name: DefaultFileSystemWriteGuardSetting
# Scope: Machine
# State: Enabled
# Source: msedge.admx

Set-RegistryValue -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Edge' -Name 'DefaultFileSystemWriteGuardSetting' -PropertyType 'DWord' -Value 2

The OMA-URI is an inferred ADMX-backed Policy CSP candidate derived from the source ADMX file name and policy name.
Some Microsoft policies use built-in Policy CSP pages whose area names don't match the ADMX file name, so verify the candidate against Microsoft Learn before deployment.
The generated payload is incomplete because one or more ADMX element values were not supplied: DefaultFileSystemWriteGuardSetting

ADMX profile candidate (OMA-URI)

./Device/Vendor/MSFT/Policy/Config/ADMX_msedge/DefaultFileSystemWriteGuardSetting

Intune remediation scripts

Detection

$ErrorActionPreference = 'Stop'
$reasons = [System.Collections.Generic.List[string]]::new()

function Test-RegistryValueExists {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return $false
    }

    return $null -ne (Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction SilentlyContinue)
}

function Test-RegistryValueEquals {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $Kind,
        [Parameter(Mandatory = $true)][object] $Expected
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return $false
    }

    $valueObject = Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction SilentlyContinue
    if ($null -eq $valueObject) {
        return $false
    }

    $actual = $valueObject.$Name
    switch ($Kind) {
        'String' { return [string]$actual -ceq [string]$Expected }
        'ExpandString' { return [string]$actual -ceq [string]$Expected }
        'DWord' { return [uint32]$actual -eq [uint32]$Expected }
        'QWord' { return [uint64]$actual -eq [uint64]$Expected }
        'MultiString' {
            $actualArray = @($actual)
            $expectedArray = @($Expected)
            if ($actualArray.Count -ne $expectedArray.Count) { return $false }
            for ($index = 0; $index -lt $actualArray.Count; $index++) {
                if ([string]$actualArray[$index] -cne [string]$expectedArray[$index]) { return $false }
            }
            return $true
        }
        'Binary' {
            $actualArray = [byte[]]$actual
            $expectedArray = [byte[]]$Expected
            if ($actualArray.Length -ne $expectedArray.Length) { return $false }
            for ($index = 0; $index -lt $actualArray.Length; $index++) {
                if ($actualArray[$index] -ne $expectedArray[$index]) { return $false }
            }
            return $true
        }
        default { return [string]$actual -ceq [string]$Expected }
    }
}

# Policy: Control use of the File System API for writing
# Name: DefaultFileSystemWriteGuardSetting
# Scope: Machine
# State: Enabled
# Source: msedge.admx

$isMatch = Test-RegistryValueEquals -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Edge' -Name 'DefaultFileSystemWriteGuardSetting' -Kind 'DWord' -Expected 2
if (-not $isMatch) {
    $reasons.Add('Value mismatch: HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Edge\DefaultFileSystemWriteGuardSetting') | Out-Null
}

if ($reasons.Count -eq 0) {
    Write-Output 'Compliant'
    exit 0
}

$reasons | ForEach-Object { Write-Output $_ }
exit 1

Remediation

$ErrorActionPreference = 'Stop'

function Set-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $PropertyType,
        [Parameter(Mandatory = $true)][object] $Value
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        New-Item -Path $Path -Force | Out-Null
    }

    New-ItemProperty -LiteralPath $Path -Name $Name -PropertyType $PropertyType -Value $Value -Force | Out-Null
}

function Remove-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (Test-Path -LiteralPath $Path) {
        Remove-ItemProperty -LiteralPath $Path -Name $Name -Force -ErrorAction SilentlyContinue
    }
}

function Clear-RegistryKeyValues {
    param(
        [Parameter(Mandatory = $true)][string] $Path
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return
    }

    foreach ($propertyName in (Get-Item -LiteralPath $Path).Property) {
        Remove-ItemProperty -LiteralPath $Path -Name $propertyName -Force -ErrorAction SilentlyContinue
    }
}

# Policy: Control use of the File System API for writing
# Name: DefaultFileSystemWriteGuardSetting
# Scope: Machine
# State: Enabled
# Source: msedge.admx

Set-RegistryValue -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Edge' -Name 'DefaultFileSystemWriteGuardSetting' -PropertyType 'DWord' -Value 2

History 37 retained releases

150.0.4078.8016 Jul 2026
- Already present in the first release ChangeIntel keeps.

36 later releases left it unchanged.

Template

Internal name: DefaultFileSystemWriteGuardSetting
Namespace: Microsoft.Policies.Edge
Template file: msedge.admx
Release: Microsoft Edge 155.0.4283.62 · file set 0a733b0040dbbf02…

Definition, editor controls and support

Definition

<policy class="Both" displayName="$(string.DefaultFileSystemWriteGuardSetting)" explainText="$(string.DefaultFileSystemWriteGuardSetting_Explain)" key="Software\Policies\Microsoft\Edge" name="DefaultFileSystemWriteGuardSetting" presentation="$(presentation.DefaultFileSystemWriteGuardSetting)" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Microsoft.Policies.Edge:ContentSettings" />
      <supportedOn ref="Microsoft.Policies.Edge:SUPPORTED_WIN7_V86" />
      <elements>
        <enum id="DefaultFileSystemWriteGuardSetting" valueName="DefaultFileSystemWriteGuardSetting">
          <item displayName="$(string.DefaultFileSystemWriteGuardSetting_BlockFileSystemWrite)">
            <value>
              <decimal value="2" />
            </value>
          </item>
          <item displayName="$(string.DefaultFileSystemWriteGuardSetting_AskFileSystemWrite)">
            <value>
              <decimal value="3" />
            </value>
          </item>
        </enum>
      </elements>
    </policy>

Editor controls

<presentation id="DefaultFileSystemWriteGuardSetting" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions"><dropdownList refId="DefaultFileSystemWriteGuardSetting">Control use of the File System API for writing</dropdownList></presentation>

Supported platforms and category

Microsoft.Policies.Edge:category:ContentSettings
<category displayName="$(string.ContentSettings_group)" name="ContentSettings" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Microsoft.Policies.Edge:microsoft_edge" />
    </category>
Microsoft.Policies.Edge:category:microsoft_edge
<category displayName="$(string.microsoft_edge)" name="microsoft_edge" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
Microsoft.Policies.Edge:definition:SUPPORTED_WIN7_V86
<definition displayName="$(string.SUPPORTED_WIN7_V86)" name="SUPPORTED_WIN7_V86" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
Microsoft.Policies.Edge:category:ContentSettings
<category displayName="$(string.ContentSettings_group)" name="ContentSettings" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Microsoft.Policies.Edge:microsoft_edge" />
    </category>
<strings><string id="Microsoft.Policies.Edge:ContentSettings_group">Content settings</string></strings>
Microsoft.Policies.Edge:category:microsoft_edge
<category displayName="$(string.microsoft_edge)" name="microsoft_edge" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="Microsoft.Policies.Edge:microsoft_edge">Microsoft Edge</string></strings>
Microsoft.Policies.Edge:definition:SUPPORTED_WIN7_V86
<definition displayName="$(string.SUPPORTED_WIN7_V86)" name="SUPPORTED_WIN7_V86" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="Microsoft.Policies.Edge:SUPPORTED_WIN7_V86">Microsoft Edge version 86, Windows 7 or later</string></strings>