> Can WinHTTrack build an index of the files (htm and
> non-htm) that's downloaded to my computer, so that
> when i run WinHTTrack to resume a project, it won't
> re-download the files i already have on my
> computer?
There is no resume, Mirror, Update or Continue. You want to Cancel the
previous mirror and Continue the next time. Alternatively, pause and minimize
the application.

The cache is the index.  I do this all the time with 3.33 If Action = Continue
it will only download remaining html files and will check non-html for changes
downloading those not previously downloaded and those changed.

On an Update it will also check html files for changes and download those that
have changed. The exception is that dynamically generated pages are reported
by the server as new even if they haven't changed.

If you press Cancel the second time it stops immediately and the cache isn't
built. (That's that new versus old cache message.)