Because of the improvement-oriented nature of peer-feedback activities, students have to deal with errors (e.g., spelling and argumentation errors) when providing and processing peer-feedback on writing assignments. Despite the central role of errors in feedback activities, it is uncertain how students deal with errors and whether the dealing with errors is affected by interpersonal perceptions. Therefore, this study explores (1) whether cognitive sub-phases are distinguishable during the process of dealing with errors and (2) the extent to which dealing with errors is affected by interpersonal perceptions. Six dyads of Dutch 11th grade students provided and processed peer-feedback on argumentative texts while thinking-aloud, and they reflected on the processes in a post-interview. The think-aloud utterances and interviews were analyzed with a mixed-methods design, using quantitative content analyses, and qualitative thematic analyses. The dealing with errors during peer-feedback provision displayed two patterns: error identification either occurred simultaneously with the decoding and often any evaluation-related thoughts lacked, or error-identification occurred as a result of an interpreting/evaluating phase. Also during peer-feedback processing, two main patterns were observable: students either knew immediately whether they agreed with feedback, or they first had to study the feedback more thoroughly. Additionally, interpersonal perceptions seemed to affect most students implicitly during feedback provision, and most students explicitly during feedback processing. As such, this study provides empirical evidence for the existence of cognitive sub-phases in the process of dealing with errors during peer-feedback activities, and portrays how these activities may be affected by interpersonal perceptions.