I had a lot of trouble trying to get the parameters correct on a mirror
project.

I found that after 49,000+ files were downloaded (all pdf files) I had to stop
the program and redo some of the settings. When I started the mirroring again
I found that httrack deleted 18hrs+ of work without TELLING me it was doing
so. It would be REALLY nice if there was a warning built into the program when
this happens so that a big message would pop up on screen and tell me that the
program is going to delete all my work before continuing.