Problem
When you turn on your Mac, you are logged in without ever being prompted for your password which you have set.
Solution
You need to turn off the Auto login setting:
- Click the Apple icon in the top left.
- Click System Preferences.
- Click on the “Accounts” icon.
- Click on the padlock if it is locked and enter your password.
- Click on the “Login Options” item in the list of accounts on the left side of the “Accounts” System Preferences window.
- Uncheck the “Automatically log in as” option.