User Configuration > Administrative Templates > Microsoft Excel 2016 > Excel Options > Save
User
HKCU\software\policies\microsoft\office\16.0\excel\options
This policy setting allows you to specify the location where AutoRecover information is to be saved. Directing the location to a network drive may allow you to back up these files along with other network files. If you enable this policy setting, you may specify the location where AutoRecover information is to be saved. If you disable or you do not configure this policy setting, the default location is %userprofile%\Application Data\Microsoft\Excel.