Do not allow attachment previewing in Outlook: registry value disableattachmentpreviewingUserHKCU\software\policies\microsoft\office\16.0\outlook\preferences

Policy ID: L_DisableAttachmentPreviewing
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 › Outlook Options › Preferences › E-mail Options

Registry

disableattachmentpreviewing

REG_DWORDUser

HKCU\software\policies\microsoft\office\16.0\outlook\preferences 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\preferences]

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

CMD

:: Options (use only one)

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

PowerShell

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

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