Cached Exchange Mode (File | Cached Exchange Mode): registry value cachedexchangemodeUserHKCU\software\policies\microsoft\office\16.0\outlook\cached mode

Policy ID: L_CachedExchangeModeFileCachedExchangeMode
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 › Account Settings › Exchange › Cached Exchange Mode

Registry

cachedexchangemode

REG_DWORDUser

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

Enabled value: Depends on the option value
Element: Select Cached Exchange Mode for new profiles

Options
Item	Stored value
Download Headers	1
Download Full Items	2
Download Headers and then Full Items	3

Apply with .reg · CMD · PowerShell

.reg

Windows Registry Editor Version 5.00

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

; Options (use only one)
; Download Headers
"cachedexchangemode"=dword:00000001
; Download Full Items
"cachedexchangemode"=dword:00000002
; Download Headers and then Full Items
"cachedexchangemode"=dword:00000003

CMD

:: Options (use only one)

:: Download Headers
reg add "HKCU\software\policies\microsoft\office\16.0\outlook\cached mode" /v "cachedexchangemode" /t REG_DWORD /d 1 /f
:: Download Full Items
reg add "HKCU\software\policies\microsoft\office\16.0\outlook\cached mode" /v "cachedexchangemode" /t REG_DWORD /d 2 /f
:: Download Headers and then Full Items
reg add "HKCU\software\policies\microsoft\office\16.0\outlook\cached mode" /v "cachedexchangemode" /t REG_DWORD /d 3 /f

PowerShell

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

# Options (use only one)
# Download Headers
New-ItemProperty -Path 'HKCU:\software\policies\microsoft\office\16.0\outlook\cached mode' -Name 'cachedexchangemode' -PropertyType DWord -Value 1 -Force | Out-Null
# Download Full Items
New-ItemProperty -Path 'HKCU:\software\policies\microsoft\office\16.0\outlook\cached mode' -Name 'cachedexchangemode' -PropertyType DWord -Value 2 -Force | Out-Null
# Download Headers and then Full Items
New-ItemProperty -Path 'HKCU:\software\policies\microsoft\office\16.0\outlook\cached mode' -Name 'cachedexchangemode' -PropertyType DWord -Value 3 -Force | Out-Null