Policy
Upgrade only the default store
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.
Pack Microsoft Office
Category Microsoft Outlook 2016 / Miscellaneous / PST Settings
Policy ID
5882171f5b18 Internal name
L_UpgradeOnlyTheDefaultStore Registry
Copy registry mappings
HKCU\software\policies\microsoft\office\16.0\outlook\setup\upgradedefaultonly (enabled) = 1
HKCU\software\policies\microsoft\office\16.0\outlook\setup\upgradedefaultonly (disabled) = 0 Policy notes
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.