User Configuration > Administrative Templates > Microsoft Project 2016 > Project Options > Schedule > Scheduling options for 'Project1'
User
HKCU\software\policies\microsoft\office\16.0\ms project\options\scheduling
Specifies the unit of time (minutes, hours, days, weeks, or months) used by default in the Duration field. If you enable this setting, the unit you specify will be used if the user does not specify a unit of time when entering a duration. If you disable or do not configure this setting, the user's default setting is used.