It's your worst nightmare. There is no way to turn it off, QB doesn't care (as evidenced by this long-standing thread) and it corrupts your books on a massive level if you are not immaculately careful to undo every "auto match" which is wrong 99% of the time.  I had to file for an extension this year it was so bad. Essentially, it greatly amplifies the time it should take to do your accounting and QB cannot even entertain us with an option to turn it off. I am actively searching for an alternative software package for exclusively this reason, and the time suck  (And headaches) it creates.