Out of the blue, MAMP Pro started presenting me with an alert when I tried opening the app:
Oops, something is badly wrong!
Either you did not provide the necessary admin credentials or the MAMP PRO package could not be initialized correctly. You can either restart the application and try again or re-install the software.
I contacted support, they advised me to uninstall/reinstall and that didn’t help. The alert kept on being the only thing I saw when I tried to start the app and then it would just close.
After doing some digging around the web, I ended up here and the following command fixed it:
sudo launchctl load -w /Library/LaunchDaemons/de.appsolute.mampprohelper.plist
I suspect this might have been caused because I manually disabled MAMP Pro helper Launch Agent on macOS. Still not sure why MAMP Pro needs that running to start the app but it looks like it does.
BTW: the databases and settings for MAMP Pro are not in /Applications/MAMP but in /Library/Application Support/appsolute/MAMP PRO/