Maintaining intersubjectivity is crucial for accomplishing coordinated social action. Although conversational repair is a recognised defence of intersubjectivity and routinely used to address ostensible sources of trouble in social interaction, it is less clear how people address more equivocal trouble. This study uses conversation analysis to examine preschool classroom interaction, focusing on practices used to identify and address such trouble. Repair is found to be a recurrent frontline practice for addressing equivocal trouble, occasioning space for further information that might enable identifying a specific trouble source. Where further information is forthcoming, a range of strategies are subsequently employed to address the trouble. Where this is not possible or does not succeed, a secondary option is to progress a broader activity-in-progress. This allows for the possibility of another opportunity to identify and address the trouble. Given that misunderstandings can jeopardise interactants' ability to mutually accomplish courses of action, these practices defend intersubjectivity against the threat of equivocal trouble. (author abstract)