Leaving your computer on and unlocked when you are not in front of it is a security risk. If you leave the computer unattended, even if you are just going to the printer, you should lock your computer. It only takes a few extra seconds of your time and can protect both your data and Vanier systems from being compromised by unauthorized users.
To lock your computer: Press Ctrl + Alt + Delete and choose Lock Computer.
To unlock the computer: Press Ctrl + Alt + Delete; you will have to enter the username/password you used previously to log in to the computer.