I have exported a CSV file into Excel and spent many hours working on it. I
regularly saved it using the usual ctrl + s. However, when I went to close
Excel down it said that there an existing file with that name and do I want
to overwrite it. I selected yes - but when I went to reopen the document all
my work had disappeard and what opened was the original document.

I cannot understand how this has happened as I was also saving as I was
working.

Can anybody help please as I really do not have the time or enthusiasm to
redo all that work.

Thanks