Hi,
I've tried looking for an answer for this, but came up with nothing :-(

I've noticed that when you open a XLS file in Excel and close without
saving, the file on disk is modified. You can even see the date/time
for the XLS on disk change to the current date/time when opened, but if
you don't save, Excel changes the date/time back to what it was, making
it appear as if it wasn't changed.
If you use a binary comparison tool, you can see that there are a few
bytes that get changed. If you have made the XLS file readonly, it
never gets changed.
The binary changes can cause a lot of problems, especially when using
something like version control, synchronisation or duplicate finding
programs. Even comparing a XLS file from a ZIP archive and one that was
extracted and then opened will be shown as different.

Does anyone know of a way to stop Excel from making these background
changes?
Or maybe some pointers on where I can find an answer.

Cheers, BlueMM