diff --git a/.github/workflows/python-test.yml b/.github/workflows/python-test.yml
index 1c5432a..4a5e762 100644
--- a/.github/workflows/python-test.yml
+++ b/.github/workflows/python-test.yml
@@ -37,7 +37,6 @@ jobs:
 
       - name: Install dependencies
         run: |
-          apt-get update && apt install mpich -y
           curl -sSL https://install.python-poetry.org | python3
           poetry install --with dev --no-interaction
 
@@ -51,7 +50,6 @@ jobs:
       - name: Test with pytest
         run: |
           #!/bin/bash set -e -o pipefail
-          pip install mpi4py
           poetry run pytest --cov-report=term-missing --ignore=tests/warmth3d --cov=warmth tests/ | tee pytest-coverage.txt
 
       - name: Comment coverage
diff --git a/warmth/simulator.py b/warmth/simulator.py
index 9066479..fd8fe93 100644
--- a/warmth/simulator.py
+++ b/warmth/simulator.py
@@ -114,9 +114,9 @@ def dump_input_nodes(self, node: single_node):
     def dump_input_data(self, use_mpi=False):
         p = []
         parameter_data_path = self._parameters_path
-
-        from mpi4py import MPI
-        comm = MPI.COMM_WORLD        
+        if use_mpi:
+            from mpi4py import MPI
+            comm = MPI.COMM_WORLD        
         if (comm.rank==0):
             self._builder.parameters.dump(self._parameters_path)
             if isinstance(self._builder.grid,type(None)) is False:
@@ -193,14 +193,13 @@ def _filter_full_sim(self)->int:
 
     def _parellel_run(self, save, purge, use_mpi=False):
         filtered = self._filter_full_sim()
-        from mpi4py import MPI
-        comm = MPI.COMM_WORLD        
-        if (comm.rank==0):
-            self.setup_directory(purge)
-        p = self.dump_input_data(use_mpi=use_mpi)
-
         if use_mpi:
             from mpi4py.futures import MPIPoolExecutor
+            from mpi4py import MPI
+            comm = MPI.COMM_WORLD        
+            if (comm.rank==0):
+                self.setup_directory(purge)
+            p = self.dump_input_data(use_mpi=use_mpi)
             with MPIPoolExecutor(max_workers=20) as executor:
                 results = [executor.submit(runWorker, i) for i in p]
                 with Bar('Processing...',check_tty=False, max=len(p)) as bar:
@@ -215,6 +214,7 @@ def _parellel_run(self, save, purge, use_mpi=False):
                         except Exception as e:
                             logger.error(e)
         else:
+            p = self.dump_input_data(use_mpi=use_mpi)
             with concurrent.futures.ProcessPoolExecutor(mp_context=get_context('spawn')) as executor:
                 results = [executor.submit(runWorker, i) for i in p]
                 with Bar('Processing...',check_tty=False, max=len(p)) as bar: