Hello In DMPlexDistribute, when it is run on 1 process and sf != NULL, the output *sf is undefined. This in turn leads to crash of PetscSFDestroy, e.g. in src/dm/impls/plex/examples/tutorials/ex5.c:45. I created the corresponding pull request a minute ago. It is my first PR - please, should I write there some reviewer? Vaclav Hapla