Hi, thanks for the help. I've not visited the client again until today and I had a brainwave this morning. I couldn't change the formatting because she had filled in a lot of the cells manually and changing the font from black to white wouldn't help because
the cells are white most of the time, it's only when they're being edited that they are unreadable.
Anyway, all I did was to right click the individual sheets in the document and then "Move or Copy..." and copy them to a new workbook. It removed the black background thing and left everything else intact.
Thanks again.