User Configuration > Administrative Templates > Microsoft Excel 2016 > Excel Options > Advanced
User
HKCU\software\policies\microsoft\office\16.0\excel\options\binaryoptions
This policy setting sets the "Enable AutoComplete for cell values" option found under File tab | Options | Advanced | Editing Options. If you enable or do not configure this policy setting, Excel will allow AutoComplete for cell values. This is the default behavior. If you disable this policy setting, Excel will turn off the AutoComplete feature.