I found a way to fix the tmp files. assuming you have partial and stopped
mirror.

1. navigate to the folder in which your partially mirror is located.
2. run "httrack --continue -i"
3. let httrack run for a moment.
4. hit Ctrl-C (aka ^C) and you will be shown the following message:

"Finishing pending transfers.. press again ^C to quit."

5. Do nothing. DO NOT press ^C again. Wait as long as it takes and you will
eventually get a message:

"Done.
Thanks for using HTTrack!sfers.."

6. HTTrack will exit and if you ls your dir all the .tmp extensions will be
removed.

Why the "Httrack Users Guide (3.10)" doesn't mention anything about ^C and how
it works is a pretty glaring omission.