So I was copying some filesto my local NAS and it was taking a remarkably long time across my 10gig connection.
Later I realized this is because it was using my FUCKING WIFI TO COPY SEVENTY GIGABYTES, and I don’t know why it would ever do this? How do I make wifi the last resort? I don’t want to have to shut off wifi if I don’t have to, y’know?
This is probably the closest you can get. There might be something you can do in the terminal to make it more definitive but I couldn’t find anything. The bottom line is that if you really need to be sure you’re using Ethernet, you need to turn off Wi-Fi. That is what I do when I am remoting into others’ machines. It sucks.
Airdrop needs WiFi, but universal copy/paste does not. If you copy the pic from your Mac and paste on your laptop, it will work.
Or share via icloud files. Or add to photos. Many options. I use Dropbox for most of that kind of thing because I have decided that I will never turn my Mac Pro’s WiFi on again, after experiencing exactly the same issue. Cold turkey. Be strong. You can do it.