From: Osman Barış Malcıoğlu (
Date: Wed Nov 29 2017 - 03:42:49 CST

Dear all,
I had the same problem that was mentioned a couple of times in this forum. It took me some time to solve it, and I am forwarding my solution to save others some time.
Setting: An Ubuntu workstation with a couple of TITAN X (2017) gpus, having difficulty with indirect GLX rendering forwarded to a MacPro(2013) with ATI D500 running Mac OS 10.13.1 (High Sierra).

The problem is two fold:
1) The indirect GLX rendering in XQuartz is disabled by default. You can enable it by setting:

defaults write org.macosforge.xquartz.X11 enable_iglx -bool true

This shall add +iglx to startx script. If for some reason, it does not, you can simply edit the startx script at /opt/X11/bin/startx

2) If you have nvidia drivers installed in the remote system, you will still see that the glxinfo is failing to detect the fireGL. The nvidia drivers put GLX libraries to their own designated folders. If LD_LIBRARY_PATH is not set, the indirect GLX rendering library is not found. (You can see if this is actually your problem by running a strace to glxdemo)

in my case, I add
export LD_LIBRARY_PATH=/usr/lib/nvidia-370/
(please replace 370 with the driver you use)

and the indirect rendering now works, and vmd screen is rendered.

Here is a keyword for people searching the mail list

ERROR) A TrueColor visual is required, but not available.
ERROR) The X server is not capable of displaying double-buffered,
ERROR) RGB images with a Z buffer. Exiting ...
Info) Unable to create OpenGL window.