Outlook Security Mode

UserNeeds changes for IntuneL_OutlookSecurityMode

Supported on SUPPORTED_Windows7 (defined in the Windows templates)

5568.1000

What it does

This policy setting controls which set of security settings are enforced in Outlook. If you enable this policy setting, you can choose from four options for enforcing Outlook security settings: * Outlook Default Security - This option is the default configuration in Outlook. Users can configure security themselves, and Outlook ignores any security-related settings configured in Group Policy. * Use Security Form from 'Outlook Security Settings' Public Folder - Outlook uses the settings from the security form published in the designated public folder. * Use Security Form from 'Outlook 10 Security Settings' Public Folder - Outlook uses the settings from the security form published in the designated public folder. * Use Outlook Security Group Policy - Outlook uses security settings from Group Policy. Important - You must enable this policy setting if you want to apply the other Outlook security policy settings mentioned in this guide. If you disable or do not configure this policy setting, Outlook users can configure security for themselves, and Outlook ignores any security-related settings that are configured in Group Policy. Note - In previous versions of Outlook, when security settings were published in a form in Exchange Server public folders, users who needed these settings required the HKEY_CURRENT_USER\Software\Policies\Microsoft\Security\CheckAdminSettings registry key to be set on their computers for the settings to apply. In Outlook, the CheckAdminSettings registry key is no longer used to determine users' security settings. Instead, the Outlook Security Mode setting can be used to determine whether Outlook security should be controlled directly by Group Policy, by the security form from the Outlook Security Settings Public Folder, or by the settings on users' own computers.

What it writes

Hive: HKEY_CURRENT_USER
Registry key: software\policies\microsoft\office\16.0\outlook\security

Why it needs changes for Intune

Policy references a Windows supportedOn definition.
ADMX-INTUNE-WINDOWS-SUPPORTEDON-REFERENCE

Security baselines

Microsoft's Microsoft 365 Apps for Enterprise 2512 sets this to Enabled, in its GPO “MSFT Microsoft 365 Apps v2512 - User”.

Outlook Security Policy: Set to “Use Outlook Security Group Policy” (3).

Read from the registry.pol files in the baselines' GPO backups, downloaded from Microsoft's Security Compliance Toolkit. All baselines

Options

Option	Type	Registry value	Allowed values
Outlook Security PolicyDefault: Outlook Default Security	Drop-down list	`adminsecuritymode`	Outlook Default Security`0` Use Security Form from 'Outlook Security Settings' Public Folder`1` Use Security Form from 'Outlook 10 Security Settings' Public Folder`2` Use Outlook Security Group Policy`3`

Configure and deploy

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

Enabled · User · template defaults

Registry file (.reg)

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\outlook\security]
"adminsecuritymode"=dword:00000000

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: Outlook Security Mode
# Name: L_OutlookSecurityMode
# Scope: User
# State: Enabled
# Source: outlk16.admx

Set-RegistryValue -Path 'Registry::HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\outlook\security' -Name 'adminsecuritymode' -PropertyType 'DWord' -Value 0

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.

ADMX profile candidate (OMA-URI)

./User/Vendor/MSFT/Policy/Config/ADMX_outlk16/L_OutlookSecurityMode

ADMX SyncML candidate

<SyncML xmlns="SYNCML:SYNCML1.2">
  <SyncBody>
    <Replace>
      <CmdID>1</CmdID>
      <Item>
        <Meta>
          <Format>chr</Format>
          <Type>text/plain</Type>
        </Meta>
        <Target>
          <LocURI>./User/Vendor/MSFT/Policy/Config/ADMX_outlk16/L_OutlookSecurityMode</LocURI>
        </Target>
        <Data>&lt;enabled/&gt;
&lt;data id="L_OutlookSecurityPolicy" value="0"/&gt;</Data>
      </Item>
    </Replace>
    <Final/>
  </SyncBody>
</SyncML>

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: Outlook Security Mode
# Name: L_OutlookSecurityMode
# Scope: User
# State: Enabled
# Source: outlk16.admx

$isMatch = Test-RegistryValueEquals -Path 'Registry::HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\outlook\security' -Name 'adminsecuritymode' -Kind 'DWord' -Expected 0
if (-not $isMatch) {
    $reasons.Add('Value mismatch: HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\outlook\security\adminsecuritymode') | 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: Outlook Security Mode
# Name: L_OutlookSecurityMode
# Scope: User
# State: Enabled
# Source: outlk16.admx

Set-RegistryValue -Path 'Registry::HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\outlook\security' -Name 'adminsecuritymode' -PropertyType 'DWord' -Value 0

History 1 retained release

5568.100010 Aug 2026
- Already present in the first release ChangeIntel keeps.

Template

Internal name: L_OutlookSecurityMode
Namespace: outlk16.Office.Microsoft.Policies.Windows
Template file: outlk16.admx
Release: Microsoft 365 Apps 5568.1000 · file set 8be05d876aae137d…

Definition, editor controls and support

Definition

<policy Area="Security Baseline" AreaCategory="Security" class="User" displayName="$(string.L_OutlookSecurityMode)" explainText="$(string.L_OutlookSecurityModeEXplain)" key="software\policies\microsoft\office\16.0\outlook\security" name="L_OutlookSecurityMode" presentation="$(presentation.L_OutlookSecurityMode)" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="outlk16.Office.Microsoft.Policies.Windows:L_SecurityFormsettings" />
      <supportedOn ref="Microsoft.Policies.Windows:SUPPORTED_Windows7" />
      <elements>
        <enum id="L_OutlookSecurityPolicy" valueName="adminsecuritymode">
          <item displayName="$(string.L_OutlookDefaultSecurity)">
            <value>
              <decimal value="0" />
            </value>
          </item>
          <item displayName="$(string.L_UseSecurityFormfromOutlookSecuritySeetings)">
            <value>
              <decimal value="1" />
            </value>
          </item>
          <item displayName="$(string.L_UseSecurityFormfromOutlook10)">
            <value>
              <decimal value="2" />
            </value>
          </item>
          <item displayName="$(string.L_UseOutlookSecurityPolicy)">
            <value>
              <decimal value="3" />
            </value>
          </item>
        </enum>
      </elements>
    </policy>

Editor controls

<presentation id="L_OutlookSecurityMode" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
        <dropdownList defaultItem="0" noSort="true" refId="L_OutlookSecurityPolicy">Outlook Security Policy:</dropdownList>
      </presentation>

Supported platforms and category

outlk16.Office.Microsoft.Policies.Windows:category:L_MicrosoftOfficeOutlook
<category displayName="$(string.L_MicrosoftOfficeOutlook)" name="L_MicrosoftOfficeOutlook" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
outlk16.Office.Microsoft.Policies.Windows:category:L_Security
<category displayName="$(string.L_Security)" name="L_Security" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="outlk16.Office.Microsoft.Policies.Windows:L_MicrosoftOfficeOutlook" />
    </category>
outlk16.Office.Microsoft.Policies.Windows:category:L_SecurityFormsettings
<category displayName="$(string.L_SecurityFormsettings)" name="L_SecurityFormsettings" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="outlk16.Office.Microsoft.Policies.Windows:L_Security" />
    </category>
outlk16.Office.Microsoft.Policies.Windows:unresolved:Microsoft.Policies.Windows:SUPPORTED_Windows7
<unresolved reference="Microsoft.Policies.Windows:SUPPORTED_Windows7" />
outlk16.Office.Microsoft.Policies.Windows:category:L_MicrosoftOfficeOutlook
<category displayName="$(string.L_MicrosoftOfficeOutlook)" name="L_MicrosoftOfficeOutlook" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="outlk16.Office.Microsoft.Policies.Windows:L_MicrosoftOfficeOutlook">Microsoft Outlook 2016</string></strings>
outlk16.Office.Microsoft.Policies.Windows:category:L_Security
<category displayName="$(string.L_Security)" name="L_Security" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="outlk16.Office.Microsoft.Policies.Windows:L_MicrosoftOfficeOutlook" />
    </category>
<strings><string id="outlk16.Office.Microsoft.Policies.Windows:L_Security">Security</string></strings>
outlk16.Office.Microsoft.Policies.Windows:category:L_SecurityFormsettings
<category displayName="$(string.L_SecurityFormsettings)" name="L_SecurityFormsettings" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="outlk16.Office.Microsoft.Policies.Windows:L_Security" />
    </category>
<strings><string id="outlk16.Office.Microsoft.Policies.Windows:L_SecurityFormsettings">Security Form Settings</string></strings>