If you use your Mac in a home environment, or want to allow your kids to use your Mac without the scare of them messing with your own data and account, there are a few steps to ensure safe and appropriate use by everyone. And the nice part is that it's all built-in to your beautiful Mac OS. No third-party software required.
Anyone using a computer in a public place or even a private location where others could access private information on your computer should setup a couple safe-keeping blockades. Go to the Apple menu > System Preferences > Desktop & Screensaver (alternatively you can avoid screensaver settings and instead choose to make the computer go to sleep - see below). Make sure the screensaver activation time is set to a low time frame, such as 5-15 minutes.
Setting up a Hot Corner on this menu pane will also allow you to quickly start your screensaver before walking away from your computer. If you aren't much for screensavers and prefer to make the computer to go to sleep instead, go to System Preferences > Energy Saver. Choose a time to put your display to sleep that is sooner rather than later (5-15 minutes).
Next we need to move over to System Preferences > Security & Privacy. Here, make sure "Require password..." is checked ON and set this to the desired time - the quicker you require a password, the more secure you leave your computer. Now that you have that setup, go to the main System Preferences frame > Users & Groups. Click on Login Options at the bottom of the list of computer user accounts. You must be the admin user to modify these settings - to change them, click the lock icon at the bottom left of the window and the system will prompt you for your password. On this pane, make sure Automatic Login is set to "off". This prevents someone from going right into your computer without having to login. To get past the login screen, you will need to type your password of course. While it should go without saying, it is important that your login password is secure and hard to guess. If it's easy to guess, then you've done some security work for nothing.
So now that YOUR settings are safe, let's talk a bit about what control you have over other users. There is no need to buy additional parental control software for your Mac - a wealth of control is built-in! Back in System Preferences > Users & Groups, you see a list of users on the left side. If you are the primary user of the computer and are the one managing it, you should have "Admin" under your username. If other people want to use your computer and you want to keep them out of your stuff it is easy and helpful to create accounts for each user. Click the + sign at the bottom of the user box. Choose the type of account: Standard, Sharing, Managed, or Administrator are the most used options you'll need. Most other responsible users can get by with a Standard account. A sharing account is useful for when someone is accessing the computer remotely.
Managed is the type of account you want to choose for kids or other people that should only have very limited access - managed accounts provide you wtih a wealth of parental control options all built-in to the Mac OS. Complete the name/password information. Assuming you setup a Managed account, "Enable parental controls" will be checked. Click "Open Parental Controls" and spend a good chunk of time going through the available options. Depending on the use-case and age of the user will depend on what control you setup.
Here are the areas to review and setup:
- Apps: If desired, you can choose exactly what applications the user can access
- Web: Choose to have the system try automatically to limit websites (less safe), or provide the account with a list of safe, usable websites the user can access (very safe)
- People: If your child wants to use email or iChat, you can select the individuals s/he can communicate with, and setup your own email to receive "permission requests" from senders not in your approved list (how sweet is that?!)
- Time Limits: You can setup DAYS and TIMES when the user is allowed to even use the computer, and/or setup time limits as well for how long the user can be on the system.
- Other: Just a few other tweaks on this screen; most important is to check "Limit printer administration".
That's it - now make sure the user has his/her password and they're all set. Just don't forget to password protect YOUR side with a secure password!