Hi, Some unexpected symbols were introduced while grooming my fastq file Before @DJTPB5M1:327:C3PC4ACXX:6:1104:9355:84986 1:N:0:GTCCGC GAGCCTTGCTAGGAGAGGGAAGGTGGAAGATCATCATTTCCAGGAGAGCACTGCTAGCAGGAAGCCACGTCTGCATTACACGCTTCATTAGGGACTTCCC + @@@FFFFFFFHHHE@=FDEGCCG2A7CDFHE>F<:B?BDEGGHGICHC9B@FGEHEGG;F=GHI==CE:;BBC>C>>@CC>;8=?=CA;AA>AA<AC<C< After @DJTPB5M1:327:C3PC4ACXX:6:1104:9355:84986 1:N:0:GTCCGC GAGCCTTGCTAGGAGAGGGAAGGTGGAAGATCATCATTTCCAGGAGAGCACTGCTAGCAGGAAGCCACG+1�CATTACACGCTTCATTAGGGACTTCCC + @@@FFFFFFFHHHE@=FDEGCCG2A7CDFHE>F<:B?BDEGGHGICHC9B@FGEHEGG;F=GHI==CE:;BBC>C>>@CC>;8=?=CA;AA>AA<AC<C< I relaunch this step without being able to reproduce the bug. Any ideas about this problem ? Have you guys came across the same problem before ? Regards, Philip