No, there is absolutely no memory loss known to correspond with TMS therapy. The only known side effects with TMS therapy are the rare risk of grand mal seizure and the rare risk of fatigue.
In fact, as we have learned through hundreds of patients in the last few years, it is almost a challenge just to cause any kind of harm on TMS therapy, proving its safety for most patients suffering from depression. If the technicians fail to place the pulses in the correct parts of the brain, the pulses do not seem to adversely affect those parts of the brain, making them a pointless wait in an expensive chair in the worst case.
Although memory loss will not occur from TMS therapy, the other potential risk involved comes with bipolar patients; sometimes, stimulating the dorsal lateral pre-frontal cortex can overstimulate the patient and trigger a temporary manic episode that eventually crashes back into a depressive episode. We have recently engaged in research that suggests we can avoid this complication by providing the pulses on the right side of the brain instead of the left.