I cannot export a completed game as described by cut and paste. Doing something wrong?
Are you trying to export a pgn file to yourself as an email, or are you just trying to cut and paste it from this site into a text editor such as notepad?
I just used my laptop to copy a pgn file of one of my games and pasted it into a new text file using notepad. No problem.
If you are wanting to email a game pgn file to yourself, you cannot export it from the regular game board page. You can only cut and paste it.
If you want to export it (email it) you have to go to the 'my games' page, find the game you want in whichever folder it is located in, then click on the top right of the page where it says 'manage games'. From there check the box for the game you want, then go to the top left of the page to send it as an email. (I think you can select and send more than one game in the same email if you wish.)
(This info is for when using a laptop. I don't have any experience with any other devices.)
<EDIT> I just tested, and from the 'manage games' page I sent myself 4 'in progress' games from my inbox in one email, and then sent 30 completed games (a whole page) in another email, so if you want to you can send multiple games in the same email.