Dear developers:
I updated MFiX to the latest version 22.2 on the linux platform and encountered the following error when generating the mesh. It seems that the default mfixsolver is missing. Is there a solution to this? The issue did not occur in version 21.4.
Thanks a lot!
Hi Zishou -
Thanks for the bug report. I am able to reproduce this error. It seems that due to an unfortunate error in packaging the MFiX 22.2 release, the default solver is not usable.
We apologize for the inconvenience and will issue a fix as soon as feasable.
In the meanwhile, I suggest you compile a custom solver - just click on the “wrench” icon. If your platform lacks cmake, ninja and gfortran you can get the needed prerequisites either from your distribution (apt-get) or within conda - the command conda install -c conda-forge fortran-compiler (or mamba install fortran-compiler) will install a version of gfortran from the conda-forge repository.
After clicking the Generate button in the Mesher panel, and seeing the failure you reported, you will notice that the Run (play) button in the top toolbar is now active:
If you use that instead of the Generate button you will be able to choose the custom solver you just built:
Again, sorry for the trouble, and thanks for reporting this problem.
– Charles
Thank you for your help! 
Another work-around:
$ cd $CONDA_PREFIX; cp lib/python3.9/site-packages/mfixsolver.cpython-39-x86_64-linux-gnu.so lib/python3.10/site-packages/mfixsolver.cpython-310-x86_64-linux-gnu.so