Creating opportunities for meaningful social relationships between through collaborative learning has been suggested to facilitate all students' social inclusion. However, little attention has been given to the interaction processes leading to unsuccessful knowledge co-creation in mixed-ability peer groups including students with and without special educational needs (SEN). This study addressed this research gap by conducting multimodal conversation analyses of the social exclusion during group work of students with and without SEN, and how the students with SEN responded to their positioning as unequal learning partners. The results were based on video-recordings of 24 lessons involving fifth graders in Finnish school spaces featuring open and flexible learning environments. The results showed that although the students with SEN performed relevant on-task initiations, their contributions were misaligned by ignoring, denying, invalidating their contributions, manipulating shared learning materials, or downgrading their status as help givers. Despite this, students with SEN continued to orient toward collaborative working by persistently initiating joint activities, negotiating their task performance and struggling to ensure their right to contribute. The study underlines the importance of instructing all students to create a warm learning community in which every student has equal rights to participate and to be positively recognised.