Allow commas as address separator: registry value allowcommasinrecipUserHKCU\software\policies\microsoft\office\16.0\outlook\preferences

Policy ID: L_Allowcommasasaddressseparator
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 › Advanced E-mail Options › When sending a message

Registry

allowcommasinrecip

REG_DWORDUser

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

Checked: 1
Unchecked: 0
Element: Allow commas as address separator
Value type: REG_DWORD

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)
; Checked
"allowcommasinrecip"=dword:00000001
; Unchecked
"allowcommasinrecip"=dword:00000000

CMD

:: Options (use only one)

:: Checked
reg add "HKCU\software\policies\microsoft\office\16.0\outlook\preferences" /v "allowcommasinrecip" /t REG_DWORD /d 1 /f
:: Unchecked
reg add "HKCU\software\policies\microsoft\office\16.0\outlook\preferences" /v "allowcommasinrecip" /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)
# Checked
New-ItemProperty -Path 'HKCU:\software\policies\microsoft\office\16.0\outlook\preferences' -Name 'allowcommasinrecip' -PropertyType DWord -Value 1 -Force | Out-Null
# Unchecked
New-ItemProperty -Path 'HKCU:\software\policies\microsoft\office\16.0\outlook\preferences' -Name 'allowcommasinrecip' -PropertyType DWord -Value 0 -Force | Out-Null