A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
It sounds like you may be using a very early build of Excel 2016. Go to the Excel menu and choose About Excel. Make sure you have version 16.12 or later.
How did you set up the data connection between Excel and the .mer file? What is a .mer file? Do you have an ODBC driver for it?
The data connection and refresh options apply to web query and ODBC connections.