No problem, thank you for the clarification it is clear to me now.

Usually I use a download-manager too when I have to download files greater
than 1Gb or so. Download speed using a download-manager is often much faster
than when using HTTrack.

After I did encounter the described 4Gb download issues I've tried to download
the large files separately (just by using a browser) hoping that I could merge
those separately downloaded large files into the HTTrack project by just
copying the large files into the HTTrack created website structure (into their
mirrored location as you say) on the local disk.
But unfortunately HTTrack refuses to merge or to accept the manually added
large files (it just redownloads those files again when running the HTTrack
project again) because those files are not part of the HTTrack's website
structure cache files on the local disk.

So I tried to add those large files to HTTrack's cache files as an attempt to
trick or to fool HTTrack into recognizing those already downloaded large files
and I thought it would be an easy thing to do because the HTTrack cache files
look like regular zip files (they do have the zip extension). 

But again unfortunately HTTrack cache files don't seem to have a regular zip
format but rather a zlib format for which I don't have a GUI tool available to
manipulate HTTrack's cache files. If I would have such tool I think the trick
would work and I could stop HTTrack from redownloading those large files over
and over again.


Hopefully developers are still reading this forum and do find some time to fix
the bugs reported by the HTTrack community.

HTTrack is just a great, simple and easy to use tool for mirroring websites.