In Mapudungun, the suffix -fu- typically indicates the unsuccessful realization of either an event or its expected consequences. As is the case for frustrative morphemes in several unrelated languages, when applied to a stative VP, the interpretation tends to be linked to non-continuation. Interestingly, in addition to these core readings, -fu- also occurs in conditionals conveying counterfactuality, and in a large subclass of deontic and bouletic constructions, such as the ones that express weak necessity and unattainable desires. Following recent developments in the study of both frustratives and conditionals, this article shows how a modal analysis of -fu- can integrate these different readings into a unified account.