Stop Spotify From Opening On Startup. With spotify installed, click on the start button, then search for task manager. The quickest way to change what opens on mac startup is to use special software called app cleaner & uninstaller.
Find and select users & groups from the system preferences menu. You can also disable spotify from starting up with windows using the task manager. It can easily be found by pressing the key combination [ctrl+shift+ esc] or via the start menu.