I've set my project to download an entire [website-url].com plus checked the
"get non-HTML files", "no error pages" and "no external pages" options and
added +*.PDF as a filter.

But if an old link like [another-random-url].com/file.pdf returns a HTML page
for file not found error without clearly explaining that it is a error page,
httrack starts to download the entire [another-random-url].com domain.

Is there any way to automatically prevent this?