Windows 10 silently starts the session of the second user. How to get rid of it?

Question

Windows

Home computer with Windows10pro, 64bit.
There are 2 users on the computer: Admin with admin rights and User with normal user rights.
After some of the updates, Windows noticed the following situation:
- immediately after loading Windows and logging in as any of the users, the session of the second user may be hidden (or may not be started, the pattern has not been established).
In the task manager, on the "Users" tab, two sessions are visible.
One is active under which they logged in, and the second is in the "disabled" state. RMB on a disconnected session allows you to "Exit session" and then it disappears.
In the list of applications there is not a single one running on behalf of the second (disabled) user. But if you execute "Shutdown", then a message appears that one of the users continues to work and will lose data if the work is completed .. etc.
User passwords are not blank.
Google did not help in solving this situation. The system was checked for viruses, adware and other malware - nothing was found.
Installation of applications, updates and other settings are performed from under the administrator account. Userskaya is used for toys and web surfing.
The situation is not critical for homework, but annoying.
Has anyone else encountered such a problem?
Is there an option to exclude it? (i.e. so that only the session under which you are logged in works)

Answer 1

Any of the processes that are started automatically (from autostart to services) can be started by a user created for it during installation and other than the built-in one.
There are many ways to search. You can start at C:\Users.