Locking your Mac’s display (or “sleeping” the display) can be a great security measure when paired with a user account password. While it won’t prevent the outright theft of your Mac, it can be a quick and easy way to prevent nosy family members or coworkers from getting access to your data.
Of course, sometimes laptops get stolen from coffee shops, offices, and homes, and a locked MacBook at least provides some protection of your date.
Before doing anything else, set your “Require Password” system preferences…
Configure Your System Preferences
In order for a MacBook lock screen command to be effective, you’ll first need to configure System Preferences to require your user account password when unlocking or waking up. To do this, follow these instructions:
- Click on System Preferences.
- Next, click on Security & Privacy.
- Make sure you are on the General tab.
- Check he checkbox next to Require Password
- Then, select the time interval from the Require Password
- From the Require Password pulldown menu select the amount of time you want the elapse “after sleep or screen saver begins” to require a password from these choices: immediately, 5 seconds, 1 minute, 5 minutes, 15 minutes, 1 hour, 4 hours, or 8 hours.
If you want the highest level of security, set it to “immediately” all the way up to the lowest level of security, which is 8 hours. Those who travel with their Macbook or use it in a public space might want to set the time interval to immediately, while those who only use their laptop at home might set it to longer. It’s probably not a good idea to set the time interval to re-enter the password to 8 or even 4 hours as laptops can fall into the wrong hands.
If you often find yourself accidentally locking your screen, set it to 5 seconds so that you can quickly unlock the display without having to enter your password.
Next, you’ll need to decide on the exact functionality you want: lock (sleep) the display only, or sleep the entire system.
Locking or sleeping the display will shut the display off but keep the Mac running in the background.
If you performed the steps above to require a password, users will need to enter the correct account password in order to unlock the display.
Locking your Mac’s Screen Quickly with a Keyboard Shortcut
If you have a Mac running macOS Mojave, press these three keys simultaneously to lock your screen: Command+Control+Q keys.
To lock your Mac’s screen on an older Mac, press these keys simultaneously to lock your screen: Control+Shift+Power
For older Macs with that has a built-in drive, simultaneously press the following keys to lock your screen: Control + Shift + Eject.
In both cases, you’ll see your Mac’s display shut off immediately, while the system continues to run in the background. You’ll have to login again to resume using your Mac.
Performing a lock or display sleep command is useful for situations in which you’ll only be gone for a few minutes, as it allows you to jump immediately back to work. It’s also a good idea to use if you want to lock your Mac but have applications running in the background, such as a rendering operation or an encryption sequence.
Your Mac will still chug away at its task; the only difference is that anyone without the password won’t be able to access it, interrupting the process or otherwise messing around with your Mac.
Putting your Your Mac to Sleep with Keyboard Shortcuts
This option will put your Mac’s CPU to sleep rather than just locking the screen. MacBook owners are familiar with sleep; it occurs every time they shut their computer’s lid, or automatically after a user-defined period of time.
On macOS Mojave and other newer versions of macOS, press these three keys simultaneously to put your Mac to sleep: Command + Option + Power.
If you have an older Mac with an optical drive, you can put it to sleep by pressing these three keys simultaneously: Command + Option + Eject.
These commands will cause your Mac’s CPU to sleep immediately, shutting down all functions and requiring a password to resume using your MacBook.
Locking or putting your Mac to sleep from the Apple Menu
If you prefer to use the Apple Menu to keyboard combinations, you can choose either the sleep or the lock option from the Apple Menu. You can always find the Apple menu in the upper left of your Mac screen, scrolling down to select either Sleep or Lock Screen.
When to Put your Mac to Sleep
Users running on battery power may prefer to put their Mac to sleep to save power. The practical effect is the same (preventing others from accessing your Mac), but this latter option saves battery power while the user is away.
On the other hand, putting your Mac to sleep will stop all background tasks as it puts the CPU to sleep, so it may not be the ideal option for users who want their Macs to keep working while they grab a coffee or stop for a bathroom break.
Also, it takes longer to wake up from a sleep state than from a display lock state, although on modern Macs with fast SSD storage the time difference between the two sleep options has shrunk considerably.
We at TechJunkie recommend that Mac users experiment with both options to find the one that suits them best for different situations. It’s also likely that users, especially those “on the go” with MacBooks, will find occasion to use both options more frequently than those who mostly use their Macs at home.Road warriors are more likely to need to save battery life and be more concerned about their Macbook being lost or stolen.
Of course, it’s not a good idea to leave your Mac in a public place but realistically you might go get a coffee refill leaving your Mac at your table. It’s at least some peace of mind to know that your data will be protected from opportunistic thieves that might grab your Mac.
Regardless, having a strong user account password and taking a moment to ensure that your Mac is locked even if you only step away for a few seconds are both crucial steps to protecting your data.
If you enjoyed this article, you might also like this TechJunkie tutorial: How to Edit the Hosts File on macOS (Mac OS X). 
Do you have any tips or tricks with regard to putting your MacBook to Sleep or locking your MacBook’s screen? If so, please tell us about it in a comment below.