>> The result is that previous saved information ~3Gb
>> are lost.
>> 
>> I think there is a problem with the cache.
>> 
>> Switching from "continue interruped download"
>> to "update.." makes no difference.
>> 
>> Is there a way manualy edit the cache file in order
>> to be sure that the mirroring will not delate all
>> the good files?
I don't think there is anything that you can do yourself to the cache
manually.  I've often wished that there was a utility to rebuild the cache
database (at least the known or discoverable data) by scanning the project
folder when this happens.

Assuming you are running WinHTTrack, you can go into Windows Task Manager and
kill the WinHTTrack process instead of rebooting.  Also, it may help save your
files if you change the "Do not purge old files" option in the Build tab.  At
least with that checked, the files will not be purged but I don't know if they
will be re-downloaded.

I've only run into this problem with the 3.43-7 version and not had it happen
with the 3.43-9 version (yet).  Also, I've never had it happen on an initial
mirror, but only when trying to update or continue interrupted.  I agree that
HTT seems to choke trying to open the cache database.  The log file shows
nothing useful either.

Good luck & hope it helps,
~B^D