Abstract: The invention relates to improving the performance of sequence-based soft-output decoders using event cleanup processing, wherein combinations of potential error events are evaluated using an error detection code (EDC) to select events that produce a modified set of decisions that has no EDC detectable errors. The event cleanup method and associated event cleanup decoder enable to significantly improve the error rate performance of sequence-based decoders and/or significantly improve decoding efficiency compared to other known error cleanup methods.