Ooops, I started Migration Assistant!

Wanted to get going with the MacBook and decided to do the Migration Assistant to transfer from my old MacBook Pro. It says 48 hours to transfer about 150GB. It dropped to about 24 hours and has been hovering there.

This was a big mistake since there is no way to speed it up. I don't even have an USB-C to USB adapter so external hard drives are out of the question.

I don't think I can wait any longer. I think I should terminate the Migration Assistant. What will happen if I turn it off? I'm guessing I'll have to do a new install of Yosemite.

Advice?