diff --git a/elmerice/Solvers/CalvingGeometry.F90 b/elmerice/Solvers/CalvingGeometry.F90
index 8d40cce52f..3ea3e308b7 100644
--- a/elmerice/Solvers/CalvingGeometry.F90
+++ b/elmerice/Solvers/CalvingGeometry.F90
@@ -3491,14 +3491,15 @@ SUBROUTINE SwitchMesh(Model, Solver, OldMesh, NewMesh)
     TYPE(Matrix_t), POINTER :: WorkMatrix=>NULL()
     LOGICAL :: Found, Global, GlobalBubbles, Debug, DoPrevValues, &
          NoMatrix, DoOptimizeBandwidth, PrimaryVar, HasValuesInPartition, &
-         PrimarySolver
+         PrimarySolver,CreatedParMatrix
     LOGICAL, POINTER :: UnfoundNodes(:)=>NULL(), BulkUnfoundNodes(:)=>NULL()
-    INTEGER :: i,j,k,DOFs, nrows,n, dummyint
+    INTEGER :: i,j,k,DOFs, nrows,n, dummyint, ierr
     INTEGER, POINTER :: WorkPerm(:)=>NULL(), SolversToIgnore(:)=>NULL(), &
          SurfaceMaskPerm(:)=>NULL(), BottomMaskPerm(:)=>NULL()
     REAL(KIND=dp), POINTER :: WorkReal(:)=>NULL(), WorkReal2(:)=>NULL(), PArray(:,:) => NULL()
     REAL(KIND=dp) :: FrontOrientation(3), RotationMatrix(3,3), UnRotationMatrix(3,3), &
          globaleps, localeps
+    LOGICAL, ALLOCATABLE :: PartActive(:)
     CHARACTER(LEN=MAX_NAME_LEN) :: SolverName, WorkName
 
     INTERFACE
@@ -3557,6 +3558,10 @@ END SUBROUTINE InterpolateMeshToMesh
     !----------------------------------------------
 
     Var => OldMesh % Variables
+
+    ALLOCATE(PartActive(ParEnv % PEs))
+    CreatedParMatrix = .FALSE.
+
     DO WHILE( ASSOCIATED(Var) )
 
        DoPrevValues = ASSOCIATED(Var % PrevValues)
@@ -3635,6 +3640,9 @@ END SUBROUTINE InterpolateMeshToMesh
                 END IF
              END IF
 
+             IF(.NOT. CreatedParMatrix) &
+              CALL MPI_AllGather(.NOT. NoMatrix, 1, MPI_LOGICAL, PartActive, 1, MPI_LOGICAL, ELMER_COMM_WORLD, ierr)
+
              IF ( ASSOCIATED(Var % EigenValues) ) THEN
                 n = SIZE(Var % EigenValues)
 
@@ -3678,6 +3686,20 @@ END SUBROUTINE InterpolateMeshToMesh
              IF(ASSOCIATED(WorkSolver % Matrix)) CALL FreeMatrix(WorkSolver % Matrix)
              WorkSolver % Matrix => WorkMatrix
 
+             ! bit of a hack
+             ! since ParEnv become a pointer to ParMatrix we need to ensure one ParMatrix is formed
+             ! it needs to be from a solver present on all parts hence the all gather further up.
+             ! it seems we only need to this once per timestep/interpolation as ParEnv will have some thing
+             ! to point to. If we don't do this ParEnv % PEs, % MyPE etc. all become nans mucking eveything up!
+             IF ( ASSOCIATED(WorkSolver % Matrix) .and. ALL(PartActive) .and. .NOT. CreatedParMatrix) THEN
+                IF (.NOT. ASSOCIATED(WorkSolver % Matrix % ParMatrix) ) THEN
+                  WorkSolver % Mesh => NewMesh
+
+                  CALL ParallelInitMatrix( WorkSolver, WorkSolver % Matrix, WorkPerm)
+                  CreatedParMatrix = .TRUE.
+                END IF
+             END IF
+
              NULLIFY(WorkMatrix)
 
              !NOTE: We don't switch Solver % Variable here, because