Upgrade only the default store

Supported on: At least Windows Server 2008 R2 or Windows 7

Registry

HKCU software\policies\microsoft\office\16.0\outlook\setup

Value name: upgradedefaultonly

Enabled: upgradedefaultonly = 1

Disabled: upgradedefaultonly = 0

Description

This policy setting allows you to specify that only the default data file is upgraded on the first boot of Outlook. If you enable this policy setting, only the data file associated with your delivery mailbox is upgraded. If you disable or do not configure this policy setting, all Outlook Data Files are upgraded.