The discussion I want to answer is locked, so I can't post this answer directly onto it. But, I had a the same problem refreshing my Excel Data in Tableau Desktop as well. Then I went to the "Data" source and clicked on "Edit Data Connection" for my source. I noticed the file was pointing to some Temp Excel file that Tableau had stored on my computer instead of my actual updated workbook. Once I redirected the connection to my updated Excel Workbook, the data was refreshed in the Tableau workbook.