Protect your Mac by setting a password to wake up your Mac from the screen saver or after it's been asleep.
Open [System Preferences] by clicking on the [Apple] icon.
Click on the [Security and Privacy] icon.
Click the [gold lock] icon.
Enter your adminstrator username and password for the computer.
Make sure that the [Require password] is checked and is set to [immediately] after sleep or screen saver begins.
Click the [gold lock] icon again to save the settings.