In this paper, we investigate the effect of carrier frequency offset (CFO) on the sum-rate of block-wise single car- rier (SC) massive MIMO systems. Based on the user knowledge regarding the channel conditions, we consider three different scenarios. In the first scenario, the users know the expectation of the effective channel including the CFO effect in the time domain. In the second scenario, the users know the expectation of the effective channel including the effect of the CFO in the frequency domain. In the third scenario, the users know the expectation of the effective channel without the effect of the CFO. We show that in the first scenario, the effect of the CFO can be completely compensated. We also show that for finite number of base station (BS) antennas, the sum-rate in the second scenario is higher than that of the third scenario. However, as the number of BS antennas tends to infinity, the sum-rate in the former case is bounded and in the later case it tends to infinity.