Well done MrExcel for perhaps the most obvious answer in the world! I had again encountered the IV maximum again 2 days ago ..... and did have .xls files inherited from long before I hopped up to 2007 from 2003! I have had to step up to .xlsx yesterday only because my new mobile won't read .xls files without updating them. So, quite coincidentally, I have discovered the solution. I only googled my query (max no. of columns in Excel 2010) just to find out why I could suddenly go way beyond IV !!! so, once again, thanks for the dead simple answer!! ;--)))
Chris