the assimilation model is an integrative model that can be applied to any kind of therapeutic setting for describing the process of change. the assimilation of problematic experiences scale (apes) describes the process of assimilation of problematic experiences in therapy. although the apes presents an orderly sequence, studies have shown that assimilation process is not smooth; instead it seems to follow a sawtoothed path, with advances followed by setbacks or reversals, particularly in cognitive psychotherapies. in this paper, we report an analysis of assimilation setbacks in the process of of a good-outcome client, maría, treated with linguistic therapy of evaluation are analyzed. the sample is composed of 105 setbacks taken from analysis of maría's assimilation of three main problems. the reasons for most of the setbacks could be classified in one of three categories: the zone of proximal development, the balance metaphor, and multiple strands. each of these categories can be understood as a consequence of the cognitive strategy and thus part of the process of cognitive therapy rather than a deviation or failure. in this sense setbacks, framed in the assimilation model, reflect some of the main characteristics of cognitive therapy. nevertheless, we could not exclude the possibility that setbacks could mark a prospective drop-out; therefore, therapists should pay attention and resolve them.