Conservation projects have a lifecycle; they are born, they grow, and they can die. However, researchers know little about how the legacy of a project that failed to deliver upon its promised goals affects former participants’ willingness to participate in future conservation programming. We utilize a natural experiment—an expiration of a Reduced Emissions from Deforestation and Land Degradation (REDD+) readiness project that failed to yield payments in Pemba Zanzibar − to explore whether and how exposure to REDD+ has influenced residents’ willingness to participate in a proposed future payment for ecosystem initiative (PES). We develop a simple causal model and analyse willingness to accept data from treated and non-treated shehia (ward), showing how exposure to REDD+ affected former participants’ willingness to engage with future PES projects and how this is moderated by factors shown in previous studies to be key indicators of uptake. Contrary to our expectations, we find that exposure to REDD+ is associated with fewer protest bids and higher levels of expected future participation. We find strong evidence that use values, wealth, loss aversion, environmental attitudes, and social desirability mediate this effect. We discuss these findings concerning Pemba and end with suggestions for conservationists establishing programs with uncertain futures. •How do project failures affect former participants’ willingness to participate in future projects?•Exposure to a failed REDD+ program increased expected future participation and decreased protests.•Exposure to REDD+ dampens the moderating effect of use-values, social pressure, and environmental concern.•There is little evidence of a commodification of nature or motivational crowding out.