Management Research Review, v. 37, n. 3, pp. 261-287. Abstract Purpose: The purpose of this case study was to identify how the human factor influenced the 2010 acquisition of company X’s cement factory, located in town C in the Brazilian State of Goiás, by the multinational company A. Design/methodology/approach: Seventeen in-depth interviews were conducted with employees who participated of the acquisition process: 15 with professionals with leadership roles at the factory, the others with company A corporate executives. The data collected were qualitatively treated using discourse analysis to unveil the perceptions of the interviewees. Findings: The discussion involved topics such as: resistance to change, uncertainty, employees’ expectations and commitment, stress, employee turnover and retention. The present study contextualizes existing theoretical approaches, and its main conclusion confirms that not all M&A processes cause permanent negative impacts that lead to the failure of the acquisition or are perceived as a strong and lasting source of uncertainty by the employees of the involved companies. On the contrary, depending mainly on the perception, employees have of their working conditions at the time the acquisition process takes place; on the strategic relevance of the acquisition to the acquiring company (its motivation); on how the process is managed by the executives of the acquiring company; on the communication strategy employed by the acquiring company, as well as on the understanding of the cultural setting; and on the acquiring company having an organizational culture with policies that value employees, the community and sustainability; this change can be perceived as favourable by employees thus fostering a successful acculturation and outcome. Finally, this study is considered valuable to researchers and practitioners as it indicates that although the human factor is not considered a priority in most M&A processes, it is clearly paramount to its success or failure, specially in lock-in situations when the acquiring and acquired companies have complementary and reciprocal interdependencies. Research limitations/implications: In spite of the contributions of this research to the field of studies on M&A, the authors have to acknowledge limitations, such us: as town C was a small factory at the time of the acquisition, there were only 17 interviewees, which does not constitute a large sample. The possibility of a certain amount of unavoidable subjectivity in both the interviewees when relating their experience and the interviewer when analyzing the collected data. As stated before, being a case study, results cannot be generalized. Originality/value: This research adds to the actual state of the art on M&A signalling that there should be a match between the strategies selected by the executives of the acquiring company and the specificities of the human factor and its cultural environment. Specifically, this case study contributes to theory advancement by proposing the concept of lock-in in M&A.