diff --git a/poisson/discrete/linear_problem.py b/poisson/discrete/linear_problem.py
index a744a0c95108262ffb4e65b693d293ffc7ab6247..775abcd725e11d046b16674c4d8cdd3e4c605d24 100644
--- a/poisson/discrete/linear_problem.py
+++ b/poisson/discrete/linear_problem.py
@@ -649,7 +649,6 @@ class LinearProblem(object):
         self.lhs_sparse = None
         self.rhs_sparse_mat = None
         self.rhs_vector_sparse = None
-        self.mumps_solver_obj = None
 
         self.points_input = None
         self.points_output = None