> When i download some teaching material which has 15 
> char.(directory), when i finish download the char.1-
10.
> i download 11-13, then when finishing download. i 
can 
> find char.11-13, but char.7-10 disappeared. Why?> Is it only support 10
directory?
Did you restart an interrupted mirror? The engine 
always wipe what is not present anymore (or not 
reachable) on the remote location.

There is neither directory limits nor file limits in 
HTTrack - only the filesystem may limit such things