This paper presents a methodology for solving the probabilistic optimal power flow for load shedding minimization in islanded microgrids to frequency limits satisfaction. Here, load uncertainties are considered. The peculiarities of microgrids operating in the islanded control mode are considered, such as the frequency variation and the droop control. The Unscented Transformation is employed, taking into consideration its lower number of samples. Results for a 33-bus microgrid show the accuracy of the results as well as the computational efficiency when compared with the Monte Carlo Simulation