Hello! I'm having issues running a yt 3.5.1 script to process an OffAxisProjectionPlot of some Enzo 2.5 data. Running mpi 4.0.1 I get this error: File "plot_time.py", line 28, in <module> val, loc = ds.find_max('density') File "/opt/apps/pkgs/yt/3.5.1/src/yt/data_objects/static_output.py", line 826, in find_max source.quantities.max_location(field) File "/opt/apps/pkgs/yt/3.5.1/src/yt/data_objects/derived_quantities.py", line 635, in __call__ rv = super(MaxLocation, self).__call__(field, sample_fields) File "/opt/apps/pkgs/yt/3.5.1/src/yt/data_objects/derived_quantities.py", line 591, in __call__ rv = super(SampleAtMaxFieldValues, self).__call__(field, sample_fields) File "/opt/apps/pkgs/yt/3.5.1/src/yt/data_objects/derived_quantities.py", line 68, in __call__ for sto, ds in parallel_objects(chunks, -1, storage = storage): File "/opt/apps/pkgs/yt/3.5.1/src/yt/utilities/parallel_tools/parallel_analysis_interface.py", line 520, in parallel_objects to_share, datatype = 'dict', op = 'join') File "/opt/apps/pkgs/yt/3.5.1/src/yt/utilities/parallel_tools/parallel_analysis_interface.py", line 284, in passage return func(self, *args, **kwargs) File "/opt/apps/pkgs/yt/3.5.1/src/yt/utilities/parallel_tools/parallel_analysis_interface.py", line 723, in par_combine_object data.update(self.comm.recv(source=i, tag=0)) File "mpi4py/MPI/Comm.pyx", line 1173, in mpi4py.MPI.Comm.recv File "mpi4py/MPI/msgpickle.pxi", line 302, in mpi4py.MPI.PyMPI_recv File "mpi4py/MPI/msgpickle.pxi", line 261, in mpi4py.MPI.PyMPI_recv_match P000 yt : [ERROR ] 2019-09-14 12:26:53,382 Exception: MPI_ERR_INTERN: internal error P000 yt : [ERROR ] 2019-09-14 12:26:53,383 Error occured on rank 0. I know that someone posted a similar error recently but I don't think there was a solid solution to the problem. If anyone can help please let me know. Also i'm sorry if I didn't explain this well enough, please let me know if anything is not clear. Many thanks Andy