Hi Sergio! I'll try and see if I can be of any help here! Are you trying to run oncoanalyser with BAM or FASTQ files ? Are you able to run a samtools view on the bam file in question ? And check whether the UMIs are present and in the right format perhaps ? Those would be my initial checks ! If you're able to share some of the log (or other) files from that specific process that failed, i.e.

work/a7/a7ba79fcada67adeaaebf1954b1ed5

maybe that'll provide additional information

.command.err.txt