Completely uninstall, remove, delete any reference to Coda 2 by Panic!
My guess is you probably just need to nuke your user preferences.

Open terminal and past this command (make a backup of the Mac if you don't trust this):

defaults delete com.panic.coda2


You can also make a brand new user on the Mac and try opening coda there to double check it's not some other file somewhere or it it's really something out of your user home folder.


Isolating an issue by using another user account