Activity Monitor keeps launching at startup

OK, but can you just do a double check. In the account with the problem, go

 > Log Out (username)

(do it this way, not from the 'shutdown' dialogue)

Log in, hold down 'shift' immediately after you hit 'Return'.

If you do it right this will stop all your login items from starting up. If they do start up, try it again, you didn't hit 'shift' fast enough or didn't hold it down long enough).

When you do this successfully, does Activity Monitor still start?

It sounds like part of the awful 'resume' feature.

Close Activity monitor. Don't just close the windows but actively quit the App.

Now restart in the normal way. Does it relaunch?

Any Apps that are open at the time of shut-down are liable to be relaunched unless you jump thru various hoops.

If the suggestion works, let us know. There is a simple way to make it a permanent feature.

So what is in your startup items (eg. such as an Automator script that could set off Activity monitor, for instance)?

Thank you! I just got a new MacBook and that problem was driving me nuts. Used your suggestion and it worked! :)