If something goes wrong when running CMake please try again with an empty or newly created build-directory! This is very first thing you should try!
Please read the CMake output carefully. Often it will tell you what went wrong.
Also consider using the command line for CMake configuration as lots of CMake options (which modify requirements on third-party libraries) have to be set via the command line before CMake ran for the first time. E.g. when building with PETSc the following fails:
When clicking Configure, CMake runs without
OGS_USE_PETSC enabled and picks a VTK library which is not compiled for MPI usage. The picked VTK library is cached and never modified. So when enabling PETSc it still uses the old (and now wrong) VTK library.
So you have to use the CMake command line:
The following options are affected by this behavior and should not be changed after initially set (this means do not use
ccmake or CMake-GUI for the first CMake run):
Check also Conans troubleshooting page if you use Conan for dependencies.