Editing default file

[ptillisch]

@sonofcy

I created folder default in the sketchbook folder then placed the default.ino (my version) in the default folder.

There are more steps than that. Did you carefully follow all the steps provided in the linked post?:

@UKHeliBob

1. Press the Ctrl+Shift+P keyboard shortcut (Command+Shift+P for macOS users) to open the "Command Palette".
2. Select the "Preferences: Open Settings (UI)" command from the menu.
3. A "Preferences" tab will now open in the IDE. In the "Search Settings" field, type arduino.sketch.inoBlueprint
4. Add the path to the file containing your custom new sketch content in the field under the "Sketch: Ino Blueprint" setting.
5. Click the X icon on the "Preferences" tab.
6. Select File > Quit from the Arduino IDE menus.
7. Start the Arduino IDE.

@BitSeeker

It doesn't work (using version 2.3.4).

I just tried and it works for me.