Quickly lock your Mac without putting it to sleep

When I converted from Windows, I was used to quickly locking my computer buy hitting Ctrl-Alt-Delete and then selecting the 'lock computer' option.  On a Mac, there isn't a direct equivalent to Ctrl-Alt-Delete, but there's another method that let's you lock your desktop quickly without having to put the computer to sleep or log off.

The method involves setting your screen saver to require a password upon waking, and assigning a 'hot corner' so initiating the screen saver takes no time at all.  It also assumes that your user account requires a password to log in.

It only takes a minute to set it up.  Here's what you need to do:

* Open System Preferences (if it's not in your Dock, you can go to > System Preferences at the top of the screen)
* From the System Preferences screen, click the "Desktop & Screen Saver" icon under "Personal" settings.
* There are two panels, "Desktop" and "Screen Saver".  If the Screen Saver isn't the active panel, select it.
* Click the "Hot Corners" button at the bottom left-hand corner of the panel.
* The four select controls represent the four corners of your screen.  Set the top left-hand select control to "Start Screen Saver".
* Click the "OK" button.

You can now start the screen saver any time you like by putting the mouse at the top left of the screen and not moving it for two or three seconds.  Now lets make sure your computer will require a password when it wakes from the screen saver:

* If you closed System Preferences, open it.
* Click the "Security" icon under "Personal" settings.
* There are three panels: "General", "File Vault" and "Firewall."  With the "General" panel selected ensure the "Require password to wake this computer from sleep or screen saver" checkbox is checked.
* Close System Preferences.

That's it! Now, to lock your Mac at any time all you need to do is drag your mouse to the top left-hand corner of the screen.  Your screen saver will automatically start in two or three seconds.  Then, when you later wake the computer it will prompt you (or anyone else!) for a password to unlock it.