The paper studies the patterns of change in the range of rotor autobalancing stability resulting from the static unbalance operational increases. It considers the rotor, which performs the plane motion. It is stated that during the process of rotor unbalance growth there is extreme increase and then decrease in the lower boundary of autobalancing stability range. At the same time there are the smallest stability margin and the highest level of residual vibration of rotating machine. The analytical formula used for the determination of the highest possible in-use autobalancing stability boundary is given. The qualitative difference in the behavior of both two-bodies and multi-bodies autobalancers is shown.