I’ve been car shopping lately and have come across two instances where the car is advertised as a “Carfax 1-owner” vehicle, but the car has actually had two owners. Carfax.com does in fact report 1 owner, but when checking the vehicle with Experian AutoCheck, they report 2 owners. In one case I was actually able to determine Experian was the one that was correct, because the dealership had all of the sales records for the car in the glove box.
Don’t trust Carfax.