Core knowledge theories advocate the primacy of fundamental principles that constrain cognitive development from early infancy. However, there is concern that core knowledge of object properties does not constrain older preschoolers’ reasoning during manual search. Here we address in detail both failure and success on two well-established search measures that require reasoning about solidity. We show that poor performance arises from an inability to engage the appropriate search strategy rather than a simple failure of core knowledge. Moreover, we demonstrate that successful search is positively correlated with inhibitory control. We believe that toddlers’ manual search for an occluded object reflects a general capacity to deploy inhibition so that search behaviour can be guided by core knowledge.