>    I have noticed that when i tried to copy a
> website, HTTRACK copies the website well but when it
> has finished copying the website, it then starts
> deleting the files again.

Files no longer referenced on the site are no longer referenced in the mirror
and thus are removed.

If that's more than a few, it's possible you're overloading the site, getting
errors instead of the pages. Look in the log file and reduce
connections/second.

Also if you have intermittent network problems, same result. I run with
timeout=60 retry=9.

You can set the Do Not Purge. It won't delete anything but can result in lots
of duplicate files. One method is to update with dnp and once you get a good
mirror, update once more with out dnp.