We all have apps that we use all the time, or helper apps that run in the background. Many will have a preference setting to start automatically at startup, some won’t. And then, we have the pesky things that insist on starting up even after we have turned off automatic startup. I’ve had helper apps for apps I’ve deleted bug me at startup. So, what can you do?
When all else fails, go to System Preferences and click on Users & Groups (Accounts on older systems), then select the Login Items tab. This will show you each and every app & helper app that is loading or at least trying to load every time you start your computer. See the one you that’s bugging you? Highlight it and tap the little minus sign. That’s it. The next time you start your computer, the offending piece of software won’t bug you and maybe slow down your startup. Delete something by mistake or want to add something to start automatically? Press the plus sign.