In order to export Data Extensions as *.CSV or *.TXT files, that are easily recognised by Excel, you will have to utilise a special type of Data Extract.
The type is called File Convert (if it's not available in your account, ask Salesforce support and they will enable it for you).
Choose one target encoding. Currently, you can convert the file to:
The final Automation workflow will consist of 3 Activities.
- Data Extract type Data Extension Extract (extracts your Data Extension to a Safe House)
- Data Extract type File Convert (converts your Extract to the desired encoding)
- File Transfer (moves your file from Safe House to the SFTP)
%%Second%% Wildcard in the file naming pattern. Processing takes some time and the consecutive Activities will have issues. To be safe, I would recommend avoiding
%%Minute%% Wildcard as well.