Preferred PST Mode (Unicode/ANSI): registry value newpstformatUserHKCU\software\policies\microsoft\office\16.0\outlook

Policy ID: L_PreferredPSTModeUnicodeANSI
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 › Miscellaneous › PST Settings

Registry

newpstformat

REG_DWORDUser

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

Enabled value: Depends on the option value
Element: Choose a default format for new PSTs

Options
Item	Stored value
Prefer Unicode PST	0
Prefer ANSI PST	1
Enforce Unicode PST	2
Enforce ANSI PST	3

Apply with .reg · CMD · PowerShell

.reg

Windows Registry Editor Version 5.00

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

; Options (use only one)
; Prefer Unicode PST
"newpstformat"=dword:00000000
; Prefer ANSI PST
"newpstformat"=dword:00000001
; Enforce Unicode PST
"newpstformat"=dword:00000002
; Enforce ANSI PST
"newpstformat"=dword:00000003

CMD

:: Options (use only one)

:: Prefer Unicode PST
reg add "HKCU\software\policies\microsoft\office\16.0\outlook" /v "newpstformat" /t REG_DWORD /d 0 /f
:: Prefer ANSI PST
reg add "HKCU\software\policies\microsoft\office\16.0\outlook" /v "newpstformat" /t REG_DWORD /d 1 /f
:: Enforce Unicode PST
reg add "HKCU\software\policies\microsoft\office\16.0\outlook" /v "newpstformat" /t REG_DWORD /d 2 /f
:: Enforce ANSI PST
reg add "HKCU\software\policies\microsoft\office\16.0\outlook" /v "newpstformat" /t REG_DWORD /d 3 /f

PowerShell

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

# Options (use only one)
# Prefer Unicode PST
New-ItemProperty -Path 'HKCU:\software\policies\microsoft\office\16.0\outlook' -Name 'newpstformat' -PropertyType DWord -Value 0 -Force | Out-Null
# Prefer ANSI PST
New-ItemProperty -Path 'HKCU:\software\policies\microsoft\office\16.0\outlook' -Name 'newpstformat' -PropertyType DWord -Value 1 -Force | Out-Null
# Enforce Unicode PST
New-ItemProperty -Path 'HKCU:\software\policies\microsoft\office\16.0\outlook' -Name 'newpstformat' -PropertyType DWord -Value 2 -Force | Out-Null
# Enforce ANSI PST
New-ItemProperty -Path 'HKCU:\software\policies\microsoft\office\16.0\outlook' -Name 'newpstformat' -PropertyType DWord -Value 3 -Force | Out-Null