Hi, ok that works now. At NLO if I generate events with the default pdf set (nn23nlo) it crashes with the following error: PROCNLO_loop_sm_0>systematics run_02 INFO: Running Systematic computation INFO: Idle: 1, Running: 3, Completed: 0 [ current time: 17h12 ] WARNING: program /opt/local/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python /Users/evryonidou/Desktop/python_syscalc/PROCNLO_loop_sm_0/bin/internal/systematics.py events.lhe.gz ./tmp_0_events.lhe.gz --start_event=0 --stop_event=2500 --result=./log_sys_0.txt --lhapdf_config=lhapdf-config launch ends with non zero status: 1. Stop all computation WARNING: program /opt/local/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python /Users/evryonidou/Desktop/python_syscalc/PROCNLO_loop_sm_0/bin/internal/systematics.py events.lhe.gz ./tmp_1_events.lhe.gz --start_event=2500 --stop_event=5000 --result=./log_sys_1.txt --lhapdf_config=lhapdf-config launch ends with non zero status: 1. Stop all computation Command "systematics run_02" interrupted with error: Exception : program /opt/local/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python /Users/evryonidou/Desktop/python_syscalc/PROCNLO_loop_sm_0/bin/internal/systematics.py events.lhe.gz ./tmp_0_events.lhe.gz --start_event=0 --stop_event=2500 --result=./log_sys_0.txt --lhapdf_config=lhapdf-config launch ends with non zero status: 1. Stop all computation If I generate events with lhapdf then it works fine. Cheers, Eleni > On 22 Aug 2016, at 21:00, Olivier Mattelaer