By default, Spotify starts automatically each time you connect to your Windows 10 PC. If you do not want it to run in the background and slow down the boot process, you can turn off Spotify auto-start.
Tell Spotify not to start automatically
To find this option, open the Spotify app. You can start it from the Start menu or double-click the green Spotify icon in your notification area if it is already running.
In the upper left corner of the Spotify window, click menu (…)> Edit> Preferences.
Scroll down to the bottom part of the Settings page and click the "Show Advanced Settings" button.
Look for the "Startup and Window Behavior" option - you may need to do it scroll slightly upwards.
To the right of "Open Spotify automatically after you log into the computer", click on the drop-down frame and select “No”.
You can now leave the Settings page. Spotify will not start automatically when you log in.
Disable starting Spotify via Task Manager
If you prefer not to look in Spotify settings, you can stop Spotify from starting automatically via Windows Task Manager. Task Manager has a built-in Startup tab that lets you control which programs start from computer you.
To start Task Manager, press Ctrl + Shift + Esc or right-click on the Windows taskbar and select "Task Manager".
Click the "Startup" tab. If you do not see it, click on "More Details" at the bottom window.
Locate "Spotify" in the list. Right-click and click "Disable".
Spotify's auto-start status, as shown in the "Status" column here, will now be "Disabled". It will no longer start at startup.
Do not hesitate to disable any other auto-start program in the same way. Note that programs will not be able to complete their work on background if you do this - for example, if you turn it off Microsoft OneDrive on the Startup tab, it will not automatically sync your files after you log in until you start OneDrive automatically.