I want to edit the seatle.master master page for my enterprise wiki site collection. So I did the following:-
I copy the seatle.html inside the SP designer.
It automatically creates two new file seatle_copy(1).html & seatle_cop(1).master.
So I click on the seatle_copy(1).master.
But I receive the following error:-
Also if I try uploading a new file inside the master page gallery I will get this error:-
Please advise ?