User Configuration > Administrative Templates > Microsoft Office 2016 > IME (Japanese)
User
HKCU\software\policies\microsoft\imejp\16.0\wswordcomment\plugins\mapi
This policy setting allows you to specify the update interval for the Outlook Contacts Dictionary. This policy setting applies to Japanese Microsoft IME only. If you enable this policy setting, you can specify the update interval. For example, if you specify "720," the Outlook Contacts Dictionary is updated every 720 minutes. If you do not configure this policy setting, the Outlook Contacts Dictionary is updated every 1440 minutes (24 hours).