Specify duration of fade out (in milliseconds): registry value timeoutUserHKCU\software\policies\microsoft\office\16.0\common\desktopalerts

Policy ID: L_Specifydurationoffadeoutinmillisec
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 › Desktop Alert

Registry

timeout

REG_DWORDUser

HKCU\software\policies\microsoft\office\16.0\common\desktopalerts Current key

Enabled value: Depends on the option value
Element: Millisec:
Value type: REG_DWORD
Minimum value: 0
Maximum value: 25000

Apply with .reg · CMD · PowerShell

.reg

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\common\desktopalerts]

; Value names and types follow the ADMX. Replace <enter value> below with your own data
"timeout"=dword:<enter value>

CMD

:: Value names and types follow the ADMX. Replace <enter value> below with your own data

reg add "HKCU\software\policies\microsoft\office\16.0\common\desktopalerts" /v "timeout" /t REG_DWORD /d "<enter value>" /f

PowerShell

# Value names and types follow the ADMX. Replace <enter value> below with your own data

New-Item -Path 'HKCU:\software\policies\microsoft\office\16.0\common\desktopalerts' -Force | Out-Null
New-ItemProperty -Path 'HKCU:\software\policies\microsoft\office\16.0\common\desktopalerts' -Name 'timeout' -PropertyType DWord -Value '<enter value>' -Force | Out-Null