If you installed some programs on Ubuntu or Linux Mint, for some reason you decided to uninstall a program or some of them. Sometimes you have problems with those uninstalled programs, they somehow are still in the start up. Means a portions of those uninstalled programs are not cleaned out from your system yet. Some uninstalled programs still load when you start up your system, but you can’t find them in ubuntu start up. Since Ubuntu 12.04, Ubuntu Startup Applications manger will only show a subset of programs to load or not when your system start up, and most of the programs in your system will be hidden.
To show all of the hidden programs in Ubuntu Startup Applications manger, go to your system terminal by searching for *terminal* or press (Ctrl + Alt + t) on your keyboard
$ sudo sed -i "s/NoDisplay=true/NoDisplay=false/g" etc/xdg/autostart/*.desktop
You will be asked for password to make sure you are authorized to perform that command on your system. After running the command, now go to your *Startup Application*, you will be able to see all the hidden startup programs.