The “open family” model is widely used as a point of reference for healthy family functioning, but potential dysfunctional aspects of open families are not well understood. A unified theory is used to integrate diverse typological models of families to build a composite clinical picture of the disabled open family. The disabled open family is found to be chaotically enmeshed, caught in its commitment to collective problem solving. Its need for closure, tolerance for ambiguity, and expressive communication style can lead to intensely emotional sustained conflicts. Stress‐related symptoms and aggressive acting out may be manifest in individuals, especially children. Dispersal of members may ultimately be necessitated by the exhausting process. Family therapy with the open family requires special attention to its style as a family and its characteristic responses to interventions. The unified theory is shown to be useful in planning strategy and choosing techniques for treatment of open families. The treatment issues connected with the pseudo‐open family, a family with open values but severely limited resources in actual operation as an open system, are also high