@JackOats I meant the /bin OR the /extra folder..... sorry for the confusion. The one where you copied basic-osc.pd a few days ago. You should delete that file ONLY and so put your system back to normal.
David.

@whale-av O.K. Done that - I think!

So from now on each saved new project file will be named '𝑚𝑎𝑖𝑛.𝑝𝑑'?

Sorry - just trying to get this straight.

@JackOats Yes....... but contained in a folder with a name of your choice...... so you can have many folders for different setups.
David.

@whale-av O.K. Understood. Thank you very much for all the effort you have put into helping me get a handle on this surprisingly complicated area - for me anyway! Very much appreciated.

Also @beem, @ddw_music & @Load074 - Thanks very much for taking the time & joining the conversation Guys. You've given me lots to think about & that's a real help.