Great job!! It works perfectly! I am trying to adapt you code to my task but I am a bit confused.   I need to make some small modifications in an Excel file before converting it to a CSV. The original excel file contains only one sheet with two tables with fix dimension. The aim is to convert this tables to a csv format. To do this I have tried to create an auxiliary sheet in which I copy each table and this sheet will be exported thanks to your code. I have found a POI+Groovy Rowcopy function here that could fit my necessity with some small modifications but I don't know how to integrate this function in the main script. Could you give me a hand? https://stackoverflow.com/questions/22627691/how-to-copy-a-row-from-existing-excel-sheet-to-a-new-excel-sheet-using-apache-po   I am newbie in Groovy, Nifi and POI.   Thanks in advance.   Regards,   ... View more