There seems to be a bug in one of the Object Desktop modules(I don't know which).
After running Terragen v4.5 by Planetside Software for 15-20 minutes, I am unable to render anything and had to restart the program to be able to render again---for 15-20 minutes before it fails again.
The only way I could get things back to normal was to uninstall Object Desktop.
I'm running Windows 10 x64 on a HP Z-840 workstation with 320GB of RAM.
Obviously, this makes Object Desktop totally useless to me, which is too bad, as I liked using it.