My experience with Free version
I ran one time and while reading the first time on its GUI , my comp abrupt shut down with a bang and reboot it.
Second time I ran , I scan the craps, OK so far, then abrupt shut down and reboot comp again.
third time after 3 days doing nothing , I ran it , within one minute did the same again.
My OS is XP and I have Crap Cleaner