Here is the process to completely uninstall a plugin on MAC.
[NOTE : If you happen to have created custom user presets, please let us know before doing the following procedure and we will explain how to back them up]
To completely uninstall a program from a MAC computer please delete the following folders :
/Application/Arturia/<instrument> MIDI control Center.app
Then try to reinstall, and keep me informed if it fixes your issue.
Do not hesitate to create a ticket on the support section of our website.