HTTrack 3.39.5 closed at '\Dev\htscache.c', line 345
Reason:
assert failed: zip_disk_write_failed

Ok, it's actually 3.40-alpha-5, so I shouldn't complain.
But the nasty dialog insisted that I reported it :)
It had open handles to new.zip, new.lst, new.txt.
Had to kill it myself.
I hope this error is not cause by the number of files in the project. 
           27338 File(s)  6.769.699.448 bytes
            1769 Dir(s)   3.092.512.768 bytes free
Don't worry, not all files are completed and took long enough.