Updating CSV data

Hello Gavin, The reason i say it is probably working correctly is the same reason the advanced editor steps were requested in your forum post-which is to see what steps are being applied. If you look at the desktop version of this process, you will see the steps look something like those below. Those steps assume two columns (see the source line) and the first row is assumed to be the headers. When you add a column the system doesn't know if the CSV was corrupt or this was an intentional change. Adding columns to the same dataset can be supported in the M language and the Desktop version...In that scenario you are deciding how to handle the data change scenario. (like the suggestion in the forum) Does that make sense? let Source = Csv.Document(File.Contents("C:\Users\chass\Documents\one.csv"),[Delimiter=",", Columns=2, Encoding=1252, QuoteStyle=QuoteStyle.None]), #"Change Type" = Table.TransformColumnTypes(Source,{{"Column1", type text}, {"Column2", type text}}), #"Promoted Headers" = Table.PromoteHeaders(#"Change Type") in #"Promoted Headers" Here is an example of people using M to modify/control the data import: https://social.technet.microsoft.com/Forums/en-US/1e40ed70-3c61-4829-ba38-85bb2e9438b0/promote-multiple-rows-to-header?forum=powerquery