> I have a site that does not use .html as its default
> file extension. That's fine. HTTrack grabs them
> okay, and changes them to .html. 
Probably cgi, jsp, asp, php etc. You can not get server side code from the
public side of a web server, only the html output. So your html output is save
with a html extention.

> The problem is, I'm
> in a situation where they have to be .htm files. I
> can't seem to find any info or an option on how to
> make HTTrack default links and files to be .htm
> instead of .html. Surely there's a way, right?
If you must have the htm extention then you must need the ISO9660 option.
Windoze treat htm and html as equivalent.