“Automatic Login” allows that a given user is automatically logged in, so there is no need to enter a password. This is obviously not secure, because everybody who has access to your Mac can get in and has access to your data including your keychain (where other passwords are stored).
How to fix it
macOS 13 – 14
- Go to “System Preferences” > “Users & Groups”
- At “Automatic log in as” choose “Off”
macOS 10.11 – 12
- Go to “System Preferences” > “Users & Groups” > “Login Options”
- At “Automatic Login” choose “Off”
