Mac stopped binding CMD-Up, which I use in Emacs and Racket

Question

CMD/up, used in both Dr Racket and Portacle (Emacs) to retrieve the last command in the buffer, has stopped working for both programs.

Other combinations with CMD do work, such as CMD/P, and CMD/X, CMD/+

I am using OS X, on a Macbook Pro

This seems to be related to a previous question (set-mark-command (C-SPC) not recognised/broken), however the stated solution for that question did not work (System Preferences > Keyboard > Shortcuts > Input Sources > Select the previous input source and uncheck). That question had assumed this was on the Emacs level but found it was on the OS level. That is obviously the case for me, as it affects more than one program.

I would greatly appreciate any help.

Answer 1

Fixed -- I apologize to take up the space after having fixed it so fast, but I think it's worth documenting for the next person who runs into this:

The basic solution (outlined in set-mark-command (C-SPC) not recognised/broken) does work, but I hadn't unchecked the right shortcut. I overlooked the fact that my particular error was due to another combination being overwritten by the keyboard shortcuts. In this case, it was "Mission Control" that was bound to CMD/up. Unchecking that in Keyboard Preferences > Shortcuts, did the trick.