I created a spreadsheet with data and formulas in Excel 2010 and emailed it to a client who is using Excel 2016. She entered some data and returned the spreadsheet to me. All the original data and formulas have been replaced by links to the file as it existed in her Outlook cache, e.g.: 'C:\Users\Client\AppData\Local\Microsoft\Windows\T emporary Internet Files\Content.Outlook\OQF0O6JB\[2017 Moon&Ref Tables.xls]January'!M12

How do we stop this from happening and is it possible to rescue the spreadsheet as she saved it?