I have an excel sheet that is automatically emailed to people as an attachment. it is formatted in landscape mode, but whenever anyone either previews it in outlook or opens it in preview mode, it shows up in portrait orientation, which breaks the layout - until they press on "edit workbook" in the top yellow warning bar.

Multiple users will be receiving this email, so I can't edit everyone's excel application settings, but is there something in the workbook that I can change so that it appear in the correct orientation while viewing in preview mode?