This is an old issue but not enough info out there on a solution so I thought I would create a post for Macs, maybe can figure from this if you have a PC.
I mistakenly installed the Avid EUCON 3.1.2 because I was looking for iPad control for my ProTools IO interface and it crashed ProTools IO interface and caused issues for LOGIC Pro, here is how I resolved it.
Macintosh HD > USERS > shift + command + . Then see screenshot for path
Delete these two files below (culprits) as well as the rest of the EUCON and EUPHONIX files I found on the computer in other screenshots.
libEuCon2.dylib
libEuConDLL.dylib
