en-US office user

Configure Simple MAPI message opening prompt

Verified with Microsoft 365/Office 5568.1000 — updated on September 4, 2026

Microsoft 365/Office 5568.1000

Supported on: At least Windows Server 2008 R2 or Windows 7

Path in the GPO console

User Configuration\Administrative Templates\Microsoft Outlook 2016\Security\Security Form Settings\Programmatic Security

Description

This policy setting allows you to specify what occurs when a program attempts to gain access to a recipient field, such as the “To” field, using Simple MAPI. If you enable this policy setting, you can choose whether Outlook always allows access to the recipient field, always disallows access to the recipient field, or prompt users to specify whether to allow or disallow access to the recipient field. If you disable or do not configure this policy setting, Outlook prompts users to specify whether to allow or disallow access to the Address Book.

Registry

HKCU software\policies\microsoft\office\16.0\outlook\security

More options available

Options

Guard behavior:
promptsimplemapiopenmessage enum
  • Prompt User -> 1 (default)
  • Automatically Approve -> 2
  • Automatically Deny -> 0

Export Builder

BETA

Configure 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: Configure Simple MAPI message opening prompt
; State: Enabled
; Supported on: At least Windows Server 2008 R2 or Windows 7

[HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\outlook\security]
"promptsimplemapiopenmessage"=dword:00000001
More formats (PowerShell, Intune, SCCM)

PowerShell

# Exported from gporais.com
# Policy: Configure Simple MAPI message opening prompt
# State: Enabled
# Supported on: At least Windows Server 2008 R2 or Windows 7
# Warning: In SYSTEM context (the Intune default), HKCU targets the SYSTEM profile. Run this script using the logged-on credentials.

$path = 'HKCU:\software\policies\microsoft\office\16.0\outlook\security'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'promptsimplemapiopenmessage' -Value 1 -Type DWord

Building a multi-setting collection? Add this setting and generate combined .reg / PowerShell / GPO scripts.

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