[IronPen]

Does anyone know how to make the right Command key perform the way it is supposed to rather than activate Mission Control? There doesn't appear to be an option for it in the Keyboard Preferences and I can't find a way to disable it.

[chabig]

Check System Preferences > Mission Control. You probably have the right command key set as the keyboard shortcut for Mission Control.

[IronPen]

I figured it out. On another Mac (a white MB) the Mission Control keys were assigned as F9-F12, so I set them the same on the MacBook Pro and now the right Command key functions as a Command key again. The prior settings used Control Up/Down Arrow to activate Mission Control and Application windows, respectively. The Command key wasn't mentioned, but it was activating Mission Control. Weird.