diff --git a/mala/descriptors/descriptor.py b/mala/descriptors/descriptor.py
index ad11b8bc3..1ec78ce65 100644
--- a/mala/descriptors/descriptor.py
+++ b/mala/descriptors/descriptor.py
@@ -526,6 +526,9 @@ def _setup_lammps(self, nx, ny, nz, outdir, lammps_dict,
         """
         from lammps import lammps
 
+        parallel_warn("Do not initialize more than one pre-processing calculation\
+in the same directory at the same time. Data may be over-written.")
+
         if self.parameters._configuration["mpi"] and \
            self.parameters._configuration["gpu"]:
             raise Exception("LAMMPS can currently only work with multiple "