Not enough displays in OSXvnc-server

Perhaps I’m missing something simple, but maybe not. Here’s my issue. I have 12 users on a MacOSX server. I want those users to be able to access their GUI if necessary whenever they need without admin intervention.

If I try to start OSXvnc in the GUI for each user at login, according to the directions for multiple sessions, I eventually get the error “Could not locate display between 5900-5909”.

On the other hand, if I try to force users to start the server from the command line, I get the error “kCGErrorRangeCheck : Window Server communications from outside of session allowed for root and console user only”.

Is there a reason for limiting the display number to ports 5900 - 5909 (it’s not an inherent limitation in VNC)? Is there a way around the limited number of displays, or around the command line running only for root or console user? If there isn’t currently, it would be a great addition to the next update.


The “auto” detect will only search between 5900-5909 to find an open display port. It stays in this “normal” range for VNC servers so as not to inadvertantly advertise on a port that most people wouldn’t want it on.

In your case, to run 12 displays, you will need to statically select some ports outside that range for at least a few of the VNC servers. Just enter the port number you wish in the GUI (or use -rfbport if you are launching command line).

The “Window Server communications from outside of session allowed for root and console user only” is an Apple security restriction that can’t easily be bypassed. It’s basically saying it doesn’t want to give screen access to someone who isn’t the logged in user.

As a curiosity – how is the performance with 12 people (or I guess 9) people all logged in? We usually see a significant degredation and are surprised that you are able to run that many.