"Mark as Defect - Continue Test" should be the preferred solution for handling defects. "Mark as Defect - Stop Test" should only be used when the state of the test has to be a certain way or there is no point is continuing. An example might be a banking app which is testing a withdrawl from an account. If there is not enough money is not in the account, there is no reason to continue replaying the test. This is a good time to use "Mark as Defect - Stop Test". Otherwise it makes more sense to us "Mark as Defect - Continue Test". Mesmer will still mark the defect for your review, but the test itself will go forward and not look like a replay failure.