xl2k and lower had an addin called autosave.xla.

If you can find an old version of that addin (old CD/floppy or an old pc???),
it'll work with newer versions of excel (through xl2007 at least).

ps.

Gord Dibben posted this:

Autosave.xla from Office 2000 or 97 will work with Excel 2002 or 2003.
If you have a previous copy, move it to your Office\Library.
To download the 97 version see here........
http://www.stat.jmu.edu/trep/Marchat/sp2001/Library.htm

wrote:

I need to have Excel save a file every 30 minutes without any input from the
user. It can overwrite the previous save each time. The "auto-recover"
doesn't give us what we need.

--

Dave Peterson