I'm managing an 8-core mac server (fully updated to Mac OSX 10.8.4, all other software is up to date). Multiple users can login remotely to use the machine. Whenever someone logs in remotely, the physical monitor that is connected to the server and sits on my desk turns on, and I can see everything that the user is doing. I can even interfere with their work if I want by moving the physical mouse that is connected to the server, or typing on the physical keyboard that is connected to the server.

Update July 30 2013 If I log in to the local monitor, a remote user can log in and see my screen / hijack my session in the same way that i (locally) can take over their session (remote). Something seems very wrong with that. What settings need to be changed?

How can I stop this behavior? It represents a security risk (other users may not want me viewing their activity, or hijacking their mouse/keyboard), and frankly it's distracting to have someone else's screen/activity going on my desk.

I've messed with a bunch of settings in system preferences, and poked around Ask Different (How to Screen Sharing / VNC to an iMac without waking the display? is close, but still unsolved) for a while, haven't found a solution that works.

Physically turning off the monitor doesn't help, since it 'wakes' up whenever there is activity. Turning the monitor around or unplugging it are also not a solutions I will accept.

Thanks for your help!

  • Could you explain your setup a bit more? Correct me if I'm wrong but to me it sounds like you have regular users logging in to the OS X server as an administrator.
    – pknz
    Jul 18, 2013 at 21:53
  • Hi pknz, you may be right on. The only user that I actually see logging in also has administrator privileges on the machine. Jul 30, 2013 at 19:09
  • I would suggest that there are bigger security issues here than users being able to take over each others session. At the moment you're relying on each staff member not to break any company rules rather than preventing them from doing so in the first place. If you yourself have physical access to the screen what is stopping you from turning it on? Maybe explain why the users need to login to server?
    – pknz
    Jul 30, 2013 at 21:23
  • We're all graduate students, and use the server for its larger-than-average computing power, to run massive simulations. Often, users have to modify the simulation software, which requires admin rights. Also, none of us is paid to be the server admin, so we share the work and whenever someone needs something done, they are entitled and empowered to take care of it themselves. To answer your question, nothing is stopping me from turning the monitor on - as the title of this post indicates, it's keeping the monitor OFF that I am concerned with. Aug 1, 2013 at 13:45
  • 1
    I'm not sure about keeping it turned off, but what about a VNC/Screen Sharing app that would "curtain" the desktop so they can't use it while you are?
    – TJ Luoma
    Apr 20, 2016 at 12:04

3 Answers 3


Are they logging in as the same user as the currently logged in user? Post-10.7, Mac OS X VNC supports logging in and either sharing the current desktop, or generating a new virtual desktop.

HOWEVER, I believe if you're logging in as the same user that's currently logged in, it will take over the computer as though you were accessing it directly. The solution would then be to create separate users for everyone who accesses the server.

Here's some info about the VNC options.

Hope this helps!

  • Hi @thankyour, the resource you linked does help, but i'm still not sure how to ensure that the physical monitor stays off. To answer your question, users are always logging in as themselves - each person has his own account, but they may leave an account logged in and disconnect from the server....then reconnect at a later time. Each user should have his own desktop. When logging in, each user is given the option to share the screen of any currently logged in user, but we never use that feature. Jul 30, 2013 at 19:16

There is a tool called "Screens" which sports a curtain mode, blocking the locally attached screen from showing anything you're doing remotely. It may require specifically their software to run to access the machine remotely, but does seem to address your issue.



A more convenient solution than logging into another user could be the Shades preferences pane which allows you to dim the screen to a degree where it's not noticable that it's on. Combined with muting the audio after remotely connecting this allows you to login to an already logged on user without concern to others. However the security and privcacy concerns remain so it's not ideal.

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