I just upgraded to the newest MacOS system Sierra 10.12 and my Indesign CS 6 is very slow and unexpectedly quit often by itself compared to before. I read in one of the forum posting that mention to quit the fontd at Activity Monitor as a workaround . This works well but when I change the font to Chinese characters, CS6 crashes.
And if you go back to that discussion you'll see that it has been pointed out over and over again that CS6 is not supported under Sierra. The fact that this one workaround helps in some instances does not change the fact that you are going to be facing issues that may not be fixable.
Hopefully someone will have a suggestion but you are effectively on your own.