That's exactly right. The connection manager file selection window won't let you complete the action unless you select a valid Excel file. This can be any Excel xlsx file. Once it accepts this, you're free to edit the file path in the Propeties window to the file that you actually need. Excel Sources or Destinations in you Data Flow still recognize xlsm and xlsb formats even though the connection manager won't let you select them. It's a pretty silly and pointless restriction on Microsoft's part, especially when it's so easy to bypass it.