Allow users to demote attachments to Level 2: registry value allowuserstolowerattachmentsUserHKCU\software\policies\microsoft\office\16.0\outlook\security

Policy ID: L_AllowUsersToLowerAttachments
Scope: User Configuration
Supported on: At least Windows Server 2008 R2 or Windows 7
Source: Microsoft 365 Apps / Office Administrative Templates (version 5568.1000)
Category: Microsoft Outlook 2016 › Security › Security Form Settings › Attachment Security

Registry

allowuserstolowerattachments

REG_DWORDUser

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

Enabled value: 1
Disabled value: 0

Apply with .reg · CMD · PowerShell

.reg

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\outlook\security]

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

CMD

:: Options (use only one)

:: Enabled
reg add "HKCU\software\policies\microsoft\office\16.0\outlook\security" /v "allowuserstolowerattachments" /t REG_DWORD /d 1 /f
:: Disabled
reg add "HKCU\software\policies\microsoft\office\16.0\outlook\security" /v "allowuserstolowerattachments" /t REG_DWORD /d 0 /f

PowerShell

# Common: create the key
New-Item -Path 'HKCU:\software\policies\microsoft\office\16.0\outlook\security' -Force | Out-Null

# Options (use only one)
# Enabled
New-ItemProperty -Path 'HKCU:\software\policies\microsoft\office\16.0\outlook\security' -Name 'allowuserstolowerattachments' -PropertyType DWord -Value 1 -Force | Out-Null
# Disabled
New-ItemProperty -Path 'HKCU:\software\policies\microsoft\office\16.0\outlook\security' -Name 'allowuserstolowerattachments' -PropertyType DWord -Value 0 -Force | Out-Null