I figured out the problem. I think it happens because one or more of the quests aren't really finishing, or maybe when they are not completed in the proper order. If you have already finished the quests and are having problems with the Ash Zombies showing up every few game days, then here is the solution: In the Command Console type this, one at a time, in the order listed: completequest ccASVSSE001_Quest completequest ccASVSSE001_QuestA completequest ccASVSSE001_QuestB completequest ccASVSSE001_QuestC completequest ccASVSSE001_QuestD completequest ccASVSSE001_QuestE Because I'm not sure which one of these quests caused the Ash Zombie problem, I just typed them all one after another. I tested this by waiting in one spot for several days and no Zombies appeared.