Hi,
Unfortunately, I don't have a Windows computer without a discrete GPU to test with. The renderer is based on VTK OpenGL window. To use an older OpenGL version, we would have to rebuild with an older VTK version (still not sure if it could solve that problem). There is also no way to disable the 3D Renderer on the standalone app. Well, you can try copying this config file
rtabmap.ini in your Documents/.rtabmap/rtabmap.ini, I closed the 3D Map view, so depending if the OpenGL renderer is created before or after it is shown, it may work.
In the previous post, when I said "without a GPU", it is the ROS version on Ubuntu. The core and GUI modules are split in two different processes, so we can use only one or both.
cheers