Mutational profiling (MaP) has become perhaps the most accurate and certainly most direct way of reading out chemical modifications in nucleic acids. ShapeMapper 2 is a completely rewritten version of our software for reading out the results of an RNA chemical probing experiment by massively parallel sequencing. ShapeMapper 2 integrates careful handling of all classes of adduct-induced sequence changes, sequence variant correction, basecall quality filters, and quality-control warnings to now identify RNA adduct sites as accurately as achieved by careful manual analysis of electrophoresis data, the prior highest-accuracy standard.