Columns are not defined for this connection manager

Question

When I open my flat file connection manager, I see a warning message:

Columns are not defined for this connection manager

How do I solve this issue, or is it even something I need to worry about?

Answer 1

Click "Columns" in the pane on the left and define the columns of your flat file.

Answer 2

I am doing an "online" course and during the steps of importing a flat file I also encountered it. I could not get it to work initially. Then I aborted the import and tried again and used the " as text qualifier (even though the columns in the file are separated). It worked and I could see the correct columns in preview.

Answer 3

I know this might sound dumb but in my case, I accidently saved the file as xlsb instead of csv. Saving the file as the correct file type resolved issue.