Dear Ernesto, I am using REDItools 1.2.1 (Pysam 0.15.2). Once I start REDItoolDnaRna.py, I also have the above problem, described as follows. I want to know what caused this error and how to fix it. Could you please have a look at this problem and help me out. Thank you very much! Best wishes, Sijia python /home/binfo/RNAediting/software/installpath/bin/REDItoolDnaRna.py -i rna.bam -j dna.bam -f reference.fa -o /home/binfo/RNAediting/sampledata/output/ -c 10,1 -q 25,25 -m 20,20 -s 2 -g 1 -u -a 6-0...