I can't get PKHeX to open either. I'm running the newest version of Mac OSX and I already chose "open anyway" in the Security & Privacy settings after downloading and unzipping it. The App is there, but when I click on it, nothing happens. Not sure what the issue is. I've run older versions of PKHeX on my Mac in the past with no issues. I've also tried downloading and installing it again, but I still can't get it to open.