Normally, you can control whether PeakHour launches at startup via Preferences > General > Launch automatically when computer starts.
Sometimes, this mechanism can become confused. If you've disabled this setting in Preferences, but PeakHour is still launching at startup, follow these steps:
Enter the following command in Terminal:
~ launchctl list | grep com.digitician.peakhour4.launchAtLoginHelper - 0 com.digitician.peakhour4.launchAtLoginHelper
In the output above, the login helper is present and enabled.
To disable and delete the login helper, enter these two commands:
~ sudo launchctl stop com.digitician.peakhour4.launchAtLoginHelper Password:
~ sudo launchctl remove com.digitician.peakhour4.launchAtLoginHelper
Note: Enter your macOS password when prompted.