We have a 3rd party tool that creates an Excel file (xls, 97/2003 format) and formats some cells in different colours. When I copy a range of cells into a newly created file (xlsx, 2007/2010 format) the colours of those formatted cells change completely - light yellow becomes depp purple etc. The same happens when I move/copy a whole worksheet into a new workbook.
The company that created the 3rd party tool can not be reached any longer (probably out of business), so I am stuck with fixing this behavious in Excel.
Why is this happening, and what can I do to prevent or work around it?