Q: Keyboard shortcut to start screen saver / lock the computer?

>System preference>Security>General

>System preference>Desktop&ScreenSaver>ScreenSaver

here select a hot corner to start screensaver

MacBook Pro6,2  Mac OS X (10.6.7), 2.4GHz IntelCore i5 320 HD 8GB RAM  15"  glossy screen

If you have your security preferences set to require a password after sleep or screen saver begins (System Preferences > Security) then you can use Control-Shift-Eject to turn sleep the display. It won't start the screen saver, but the display will go dark and you will need to enter your password to wake it up.

Another option would be to use Automator to create a service to start the screen saver and set a keyboard shortcut to turn it on.

To do this, open Automator and choose Service as the template for a new workflow. Type "screen" in the search field to locate the "Start Screen Saver" action and drag it to the workflow. Set the "Service receives selected" option to "no input". Save your workflow with the same name you want it to have in the Services menu.

Next, open System Preferences > Keyboard and go to the Keyboard Shortcuts tab. In the left column, click on Services and scroll the right column down to the bottom to find the Service you just created (it will be listed under the General category). Then assign whatever keyboard shortcut you'd like to use.

Seph put across some great options.

Another easy way to create a shortcut to start your screen saver/lock your screen is listed at:

http://lukekowald.blogspot.com/2011/11/how-to-create-mac-os-x-keyboard.html

It also includes how to setup a quick Apple Magic Trackpad gesture to activate this.

Hitting ⌃⏏ will put your display to sleep. If you don't want to use a hot corner for whatever reason (to avoid risk of accidental activation, for example) then that would be a good alternative if you require password immediately.

Easiest way I have found is to set up the auto lock on the screen save like said above and then go to keyboard> keyboard shortcuts>application shortcuts and then press the + select other under the application list and naviagate to /System/Library/Frameworks/ScreenSaver.framework/Versions/A/Resources/ScreenSav erEngine.app. Then set a hotkey and viola a lock screen that works very easily and simply.

Looking at this this isnt the best way. But I have since found a better way to do it. Open up automator and select the service template. set the Service receives to no input and select any applications in the other drop down. In the left hand side drag over Launch Application. In the drop down go down to other and again go to the same path as above. (you can also go in seperately and drag the ScreenSaver Engine into the application folder and simply select the SSE as an app) Save the automation as Launch Screen Saver or anything you want. After this go back into System Prep and go under shortcuts and go to services. Scroll down until you find your service and go to the far right and add a short cut. I've found that Control-Option-Command-L is obscure enough that it will work with most applications open. If you pick a shortcut thats more used it may not work unless the finder is selected.

Be careful when updaing to Moutain Lion. There may be a bug where the "Require password" feature is stuck on disabled. At least for me it is stuck and I am not able to enable the feature and yes I have admin rights and I know how to unlock the preferences to make changes. When I click on the feature to enable it, nothing happens.

The Automator method worked best for me.  However, in 10.8.2, when you try and choose Screen Saver app in the dropdown within Automator, the Screen Saver is greyed out.  To work around this, just drag and drop it to automator and it should recognize it..and voila!

Automater seems to be the best solution to me... no extra add-ins to install and no facny coding required.

This option seems good too: https://discussions.apple.com/message/7463133#7463133

Hello,

i was wondering if you might be able to assist me with this task,

I've follows the steps you've written, but alas no joy,

stuart

Use Alfred.

http://www.alfredapp.com

I played around with Automator and some of the other apps but I find Alfred a bit more versatile. No need to have multiple keyboard short cut apps.

So this should answer the next "what is the keyboard short cut for <blank>"

Cheers,

+Eric

Thank you, Seph. This worked great and I learned even more about my Mac (didn't even know I had an Automater). The only steps I'd add are make sure the Keyboard Shortcut you pick is not already being used and I had to restart my Mac to get the shortcut to work.