Qiao investigated the properties and topological structures of (IO,O)-fuzzy rough sets, which extended the classical conjunction operator in rough approximation operator to an overlap function O. However, there are some faults in the characterizations of (IO,O)-fuzzy rough sets, such as wrong conclusions and strict condition, even if the overlap function O is assumed to be a continuous t-norm with no non-trivial zero divisors. This paper further discusses (IO,O)-fuzzy rough sets and rectifies those faults. Moreover, some examples are presented to show those faults.