Unlike custom careers, custom Uni majors are very rare things because of how complicated they are to make. I don't think I've ever seen any produced by non-NRaas sources up for use by the general community. Thus the only Education major I am aware of is the one that comes with the NRaas Careers mod Academics add-on module. It cannot be deactivated entirely without removing the module.
http://nraas.wikispaces.com/Careers%20Academics%20Phase%20Fourteen
You would want to use MasterController to make sure that all sims in your game (unless you are starting a new one) do not have this major or a degree in it before removal or else I believe their major and/or degree would then become undefined and that could cause worse issues than the custom major staying in place. That would, of course, include sims in the instance of Uni World you are playing or intending to play in addition to your homeworld.