Conceptual models, such as UML class diagrams annotated with OCL invariants, can contain inconsistencies—such as contradictory constraints—that prevent the construction of any valid system instance. Resolving these issues requires more than automatic detection or correction: it demands a deep understanding of the domain, as improper modifications may lead to unintended behavior or violate domain semantics. Existing approaches tend to focus on inconsistency detection, localization, or limited forms of automated repair, offering little support for domain experts who must interpret complex faults and reason about suitable corrections. This paper presents an approach to assist conceptual modelers in understanding and repairing inconsistencies in UML/OCL models. This approach is based on the use of object diagrams to instantiate the model and make inconsistencies tangible. These instances serve as a diagnostic aid, allowing users to explore the implications of conflicting constraints and to evaluate multiple candidate repairs interactively. The approach is implemented in a tool integrated into the UML Specification Environment (USE), which guides users through fault analysis, helps identify root causes, and supports the assessment of alternative repairs through model exploration.