Prevent Active Directory Users From Locking Screen We've been having trouble with students in our new iMac lab not logging out, which ends up locking the screen and preventing anybody else from logging into the machine. While figuring out how to get the "Switch User" button to show would be a solution, we'd prefer to just disable the lock screen entirely.

Is there an easy way to both prevent users from locking the screen (^⌘Q) as well as disabling Sleep and Screensaver when users are logged in?

If there's a better way to approach the problem I'm all ears.

Thanks!
Assuming that you aren't granting the students admin rights on the lab computers, enable automatic log out in Security &amp; Privacy > Advanced preferences:


  macOS Sierra: Set your Mac to log out when not in use
  
  You can set your Mac to automatically log out the current user after a set period of inactivity. This helps ensure that your information is secure when your Mac is unattended.
  
  
  Choose Apple menu > System Preferences, click Security &amp; Privacy, then click General.
  Click the lock icon  to unlock it, then enter an administrator name and password.
  Click Advanced.
  Select “Log out after... minutes of inactivity.”
  Set the amount of time before the user is automatically logged out.
  


The lower threshold seems to be 5 minutes.



Using automatic log out instead of disabling sleep/screensaver and not requiring a password query has the advantage that privacy of your users and protection from third party access (i.e. other students) is retained.