I've noticed a bug in the cancel/resume feature.
If you cancel the download and let the transfers finish naturally, you have
the possibility to continue the download where you canceled last time. But if
you cancel twice (because you don't have time to wait for the ongoing download
to complete), the program will write either errors in the log or the cache
which cause the program to delete everything when you try to continue the
download at some other time.

Second bug I've discovered is related to the file download description panel
(when you click on a downloading file). If you canceled download and are
waiting for the running transfers to complete, if you have this panel open, it
prevents the program from removing the last transfer forcing you to double
cancel (and lose everything).

Having both a pause button (which saves everything for next time while
allowing the user to exit winhttrack) and a cancel button (which scrubs the
transfer) would be nice to have.