Is it set up here: Tools > Options > Attachments Under 'Content Type' Microsoft Office Excel 2010 workbook Action: Use microsoft Office excel' Note you can click on the action to see a drop down selection if you need to change it. then click on OK If it is not there then you need to set it up. right click on attachment and choose 'open' a window pops up asking what to do. choose 'Open with' and either 'Microsoft Open XML converter' (I have MS Office 2007 so can to use that option) or better still select 'Microsoft Office Excel' If the option is not available click on 'Other' See if option is now available or click on 'Browse' and in Microsoft Office, locate the Excel.exe file (it might be in a folder called 'Office 12 or another number) and click on 'Open' select: 'Do this automatically for files like this from now on' and click on OK