Morning all

We have upgraded to Office 2007 within our office, but not across the
company yet. There are a number of worksheets that I have created using the
new functions (e.g. SumIfs) that aren't available in earlier versions of
Excel, so that when other users open them in earlier versions it returns the
#Name? result in the cell and effectively buggers up my formulae.

Is there a way to have a warning pop up as someone is about to open the
workbook informing them that if they do not have Excel 2007 to abort and
contact me instead? I.e. have a proceed or cancel option before opening the
workbook, but not have to rely on Password protecting.

Thanks

Mike