How to ‘lock’ your Mac’s screen

How to ‘lock’ your Mac’s screen
Mac Tip #439, 02 June 2010

If you walk away from your computer without logging out or shutting down, then anyone nearby could potentially rummage round in your files. Whether it’s colleagues in an office, family members, or visitors, you might prefer to keep them out with a password. Here’s how to ‘lock’ your Mac’s screen.

What screensavers used to do

In the early days of computer screens it was often a good idea to set some kind of random pattern to display if the screen was left inactive for a while. If the same image was left on screen for a long time — eg a menu bar — then it could ‘burn in’. That means it would still be faintly visible even if the machine was turned off.

We’re long past those days, but ‘screensavers’ — random patterns and images — can still be fun. And if you require a password to stop the screensaver then you can keep prying eyes from looking at your documents when you step away from the computer.

Set a screensaver

Screen Saver System Preference.

To set a screensaver in Mac OS X Snow Leopard:

1. Open System Preferences from the Apple menu or Dock.
2. Click on Desktop & Screen Saver in the top row.
3. Click on the Screen Saver tab. Screensaver options are revealed.
4. Select the patterns, pictures or words you want to see from the Screen Savers column on the left. The Preview at the right shows an example of what that option will look like. To see a full-screen demo click the Test button.
5. Set the Start screen saver time slider to a delay before activating the screensaver. The shortest delay is 3 minutes.
6. If you wish, select a Hot Corner as explained below.

Hot Corners

Start Screen Saver.

Hot Corners allow you to set actions such as Starting or Disabling the screensaver. A future Tip will explain them further.

If you set a Hot Corner to start the screensaver then you can force the screensaver to start without a delay. Here’s how:

1. At Step 6 above click the Hot Corners… button. The Active Screen Corners window appears.
2. Click on the drop-down menu button for the corner you want to use, eg the bottom left corner. Select Start Screen Saver from the menu.
3. Click the OK button. When you move your mouse into that corner the screensaver will start immediately. Move the mouse again and the screensaver disappears.

Now you have the screensaver in place. It will start either after a delay when you haven’t done anything on your mac for a while, or immediately if you move the mouse to a hot corner.

But at the moment, all you have to do is move the mouse to stop the screensaver and then all the information on your Mac is readily available to anyone who looks.

Now what you need is to ‘lock’ the screensaver in place, so only authorised users can stop it.

Lock the screensaver

Screensaver lock.

To lock the screensaver in place requires a trip to the Security settings.

To lock a screensaver in Mac OS X Snow Leopard:

1. Open System Preferences from the Apple menu or Dock.
2. Click on Security in the top row.
3. Click on the General tab. Many security options become available.
4. If necessary, click the padlock icon at bottom left of the window to be able to change settings. You will have to enter the username and password for an administrator to unlock the General settings tab.
5. Check the box beside Require password after sleep or screensaver begins.
6. Choose a time period from the drop-down menu. There’s a range of times between immediately and 4 hours.

Now after the screensaver starts you will have to enter a password to stop it, although you may have up to 4 hours ‘grace’.

For example, if you chose immediately then as soon as the screensaver starts it requires a password to stop it. If you chose 5 minutes then in the first 5 minutes after activating the screensaver you would only need to move the mouse to stop it, after that you’d need the password.

Things to watch for

You will probably need to experiment with these settings. You may find you often move your mouse into a particular corner as part of your normal activity. For example, you may often visit the Apple menu. In that case, you may like to avoid setting that corner as the screensaver activation corner.

Or you may still set it as the screensaver activation corner but set a 5 seconds or 1 minute delay before the screensaver locks.

Tell us in the Comments at the website your experiences with using the screensaver for locking your screen.

Your purchases through this site help support MacTips

Take Control of Safari 5