When I receive an Excel attachement that I work on, I save it as a "Microsoft Excel Workbook". When I forward it as an attachment in an email (Windows friendly attachment box and "attach file name" boxes checked), the recipient says he can't read it as it shows up as an unrecognizable file. The original Excel file was created on a PC and the recipient is a PC user. Should I be saving it as something else (MS Workbook x.x, MS Worksheet x.x, etc.) as the drop down menu has many choices or is there something else I need to do?