In automated and semi-automated rotary milking systems, situations can arise when the teat cups are not positioned correctly, resulting in the teat cup attachment arrangement failing to grip the teat cups. The present invention provides a method and system to address this problem. In particular, a method is provided for a milking system (11), which milking system comprises a moving arrangement (13)； a plurality of milking stalls (13a) arranged thereon, each of which being provided with teat cups (15) and provided for housing a milking animal (17) during milking thereof； an automatic teat cup attachment arrangement (19) provided, for each of the milking stalls, to fetch the teat cups of the milking stall at default storage positions and to attach the teat cups to the teats of a milking animal present in the milking stall prior to the milking thereof； and an automatic teat cup returning arrangement (25) provided, for each of the milking stalls, to withdraw the teat cups of the milking stall with the purpose of returning them to the default storage positions subsequent to the milking of the milking animal present in the milking stall. According to the method, the positions of the teat cups are, for each of the milking stalls, sensed after the teat cup returning arrangement has withdrawn the teat cups of the milking stall after the milking of the milking animal present in the milking stall, but before the automatic teat cup attachment arrangement is to fetch the teat cups of the milking stall； the sensed positions of the teat cups are, for each of the milking stalls, compared with the default storage positions of the teat cups； and an action with respect to the milking system is, for each of the milking stalls, performed in if the sensed positions of the teat cups deviate from the default storage positions of the teat cups by at least a specified amount.
