After disabling the cron task by manually creating /etc/default/hylafax file and setting in there the two variables to empty (thus disabling fax archiving routine) sanity has returned to HylaFAX service:
root@stt005:~# cat /etc/default/hylafax FAXQCLEAN_OPTS="" FAXCRON_OPTS="" So I cannot reproduce this bug anymore. Sorry for the noise. Cheers, -- Camaleón