Responding to a prospective memory task in the course of an ongoing activity requires switching tasks, which typically comes at a cost in performing the ongoing activity. Similarly, when the prospective memory task is deactivated, a cost can occur when previously relevant prospective memory targets appear in the course of the ongoing activity. In three experiments with undergraduate student participants (N = 226), in which cue focality was manipulated as a function of processing overlaps, we investigated the after-effects of activated and deactivated prospective memory target events. We predicted that lower focality results in stronger after-effects when the prospective memory task is activated but in weaker after-effects when the prospective memory task is deactivated. In contrast, we predicted that higher focality results in weaker after-effects when the prospective memory task is activated but in stronger after-effects when the prospective memory task is deactivated. For activated prospective memory, the pattern of results conformed to the expectations. For deactivated prospective memory, after-effects occurred only under high process overlap situations in a zero-target condition, in which participants were instructed for the prospective memory task, but never had the opportunity to perform it, indicating the special representational status of uncompleted intentions. We discuss these findings within the process overlap framework, which allows more fine-grained distinctions than the focal versus nonfocal dichotomy.