So, this is pretty much just a warning that I feel obliged to put out there.
Maybe it's just a way of sharing my "pain". I downloaded about 50 GB of files
and mirrored a website. Took a really long time to do that. I then searched
for empty directories and found one. So like the smart guy I am, I used the
URL for that specific folder and ran the program again to "add" the files in
that folder. 50 GB vanished into thin air and I'm now the proud owner of 250
MB folder.

Don't be me. As soon as the info hits your computer, change its address and
change directories completely. As good as HTTrack is with downloads, don't
trust it with updates. I mean, seriously, couldn't there be a failsafe for 50
GB of data? Literally one teeny dialog box would have been enough. Anyway,
learned a really, really, valuable lesson today.