diff --git a/MathLib/LinAlg/PETSc/PETScLinearSolver.cpp b/MathLib/LinAlg/PETSc/PETScLinearSolver.cpp
index 566d775d5c565a6f5978421f5a1012c75468d05c..37e109a46c0073b80214294444e5bd1f3698f0cf 100644
--- a/MathLib/LinAlg/PETSc/PETScLinearSolver.cpp
+++ b/MathLib/LinAlg/PETSc/PETScLinearSolver.cpp
@@ -68,6 +68,7 @@ PETScLinearSolver::PETScLinearSolver(const std::string /*prefix*/,
         KSPSetOptionsPrefix(_solver, prefix.c_str());
     }
 
+    KSPSetInitialGuessNonzero(_solver, PETSC_TRUE);
     KSPSetFromOptions(_solver);  // set running time option
 }