Lock your computer

Always remember to lock your computer when you leave it. When you are logged in you have access to some ressources based on who you are. If you leave your computer unlocked others can exploit it.  This can lead to information that only you should be able to see and change can be viewed and edited by others - in your name.   

How to lock your Windows computer

Here you can find two different ways to lock your Windows computer

  1. Press simultaneously on Ctrl + Alt + Delete and select "Lock Computer". 
  2. Press simultaneously on the Windows button + "L".  

How to lock your Mac

Lock your screen without screen saver:

  • Go to Applications, Help programs, Main keychain.
  • Choose Settings and tick off Show status in menu bar.
  • Now, you will see a small padlock in the menu bar. Use it to lock your Mac.

Lock your screen by means off screen saver:

  • Go to System preferences, Security & Privacy.
  • Choose Require password immediately after sleep or screensaver begins (or set it to 5 seconds delay so that you can switch off the lock if you activate it by accident. 

security settings mac

  • Afterwards, Go to System Prefrefrences, Desktop & Screen Saver.
  • Choose Hot Corners.
  • Choose Start Screen Saver in the corner you wish to use and press OK.


  • Now, you can start you screensaver and thereby activate your screen lock by moving your mouse to the choosen corner. 
  • You can also activate your screensaver by pressing cmd+shift+eject.

How to lock your Linux computer

If you use Linux without graphic user interface, remember to log out when you leave the computer.

If you use a graphic user interface, Linux is as standardised as Windows or Mac. Therefore, there can be different ways to lock your screen depending on distribution and some times depending on which user interface you use.

CTRL+ALT+L works in some distributions, however, the best advice is to use the help function which is build in to find the correct way for your system.