I should have explained it first. When I start my computer, a software need elevated privilege : everything search. Often, i'm not in front of my computer when the uac prompt show up and I sometime miss it. This is not a big issue though.
I know that everything can be started using the task scheduler with high privilege but this way I often miss his taskbar icon and need to kill the process using task manager and reopen it to see his icon back in the system tray. Look like it start before explorer open, even if I set it to open with session and delay his start.