Answered
I can't change the default "open with" back to regular Illustrator when Illustrator Beta is installed.
Why can’t I set my regular illustrator to be the default open app when I have illustrator beta installed? I don’t want to use Beta for everything, but it is nice to have here and there. It doesn't give me the option to “set as default” in the “open with” drop down. On a Macbook Pro.

