The Sluggish Boot
As you install more software on Ubuntu, you may notice your computer takes significantly longer to become usable after typing your password. This is because many applications (like cloud sync clients, chat apps, and system monitors) automatically add themselves to your startup list. The moment you log into the GNOME desktop, Ubuntu launches all of these programs simultaneously in the background. While this saves you from manually clicking their icons, having ten apps fighting for CPU cycles during boot will drastically slow down your system and consume valuable RAM before you’ve even started working.
Pruning the Startup List
To drastically improve your boot times and stop Ubuntu from automatically starting unnecessary apps on login, you must manage your startup configuration using the built-in utility.
Open the main Ubuntu application launcher (press the Super/Windows key) and type Startup Applications. Click the icon that appears to open the “Startup Applications Preferences” window. Here, you will see a list of every third-party program configured to launch automatically. Review the list carefully. If you see an application you don’t need running immediately (like a game launcher or a chat app you only use occasionally), simply uncheck the box to the left of its name. Do not click “Remove” unless you want to delete the entry entirely; unchecking it safely disables the auto-start behavior while leaving the configuration intact in case you change your mind later. Click Close when finished.