I’m getting this error upon installing MFiX version 25.3 and also 25.2.1 on a new WSL2 system, using Fedora distro. I have briefly compared the vtk versions to a working setup on another unit, and they seem to be the same. Attaching the conda list.
2025-10-21 22:56:17.943 ( 3.139s) [ 719EA004F780]vtkOpenGLRenderWindow.c:701 ERR| vtkEGLRenderWindow (0x565811930200): GLEW could not be initialized: Missing GL version
conda.txt (23.5 KB)
Hi @kjetilbmoe
Unfortunately I don’t know enough about WSL to have anything useful to say here - this is not a platform we regularly test, although it should work.
If I have some time I’ll set up WSL and try it out, but I can’t guarantee anything.
Since this is really a VTK issue and not an MFiX issue, you may have better luck posting on the VTK forum: https://discourse.vtk.org
As always, search there before posting - possibly this thread will help:
Does VTK support wsl? - Support - VTK
Please let us know if you find a solution.
– Charles
Thanks, yes seems like this is related to a VTK version, it’s not so much the WSL causing this I think. I have got it all working by copying over a WSL virtual machine from another computer. It’s just not so easy to sese exactly what version is causing the problems. Thanks anyway, I just wanted to add it here in case other people are experiencing something similar.
There are just so many variables here: VTK version, WSL settings, X server settings, and various environment variables such as LIBGL_ALWAYS_INDIRECT, VTK_DEFAULT_OPENGL_WINDOW, and MESA_GL_VERSION_OVERRIDE….
What are you using for an X server? Does WSL come with a built-in X server?
Yes, X is really not an issue, it is now supported as of WSL2. Run Linux GUI apps with WSL | Microsoft Learn
I would say that there are few possibilities still, because I have MFiX working on an exact same setup, only difference is installation time. Meaning only the packages in conda differ between the two. I just haven’t sat down and compared the them, and downgraded the faulty ones.
Please send us the output of conda list (with mfix environment activated). Thanks.
Already did, first post 
Oops. Well, I can see that you are using a VTK library built for egl. It may be better to use the version built for qt.
With the mfix environment active,
conda install vtk=*=*qt*
Let us know if this helps!
That did the trick! Then the question is why are they not installed the first time? 
I have not come across this problem before.
Conda is a bit of a moving target. Dependencies are resolved at installation time, not when we build the packages. Anyhow, we have modified the conda dependency list to specify vtk=*=*qt* so future releases should work correctly.
Thanks for the report, and sorry for the trouble.
– Charles