We can often find in the literature (both popular and academic) ascriptions of complex collective duties to extensive unstructured collections of individuals. By 'complex collective duties', I mean collective duties that, plausibly, require that the individual members of an extensive unstructured collection should enact different contributory act-types to achieve an end jointly - for example, the alleged universal collective duty to end global poverty. In this paper, I argue that these duties are not action-guiding. The reason is that they do not pass what I call the 'test of action-guidance'. This test assumes the intuitive belief that a moral duty is action-guiding only if it is clear to the duty-bearer the act-type that she should enact after the ascription of the duty. Complex collective duties ascribed to extensive unstructured collections fail to pass this test because, even though each duty-bearer (that is, each member of the collection) receives guidance on the end that they should achieve jointly, it is not clear to these agents the act-type that each of them should put into practice.