User Configuration > Administrative Templates > Microsoft Office 2016 > Miscellaneous
User
HKCU\software\policies\microsoft\office\16.0\common\fileio
This policy controls when locally cached Office version documents from the server are aged out of the local cache. If you enable this policy setting, Office document versions from the server that have been locally cached for more than n days, will be deleted from the local cache. If you disable or don't configure this policy setting, Office document versions from the server that have been locally cached, will be deleted from the local cache if older than the default of one day.