diff --git a/product/ERP5/Document/SolverProcess.py b/product/ERP5/Document/SolverProcess.py
index c1ba7dab4242f961d12378e57d6b72328bf096d5..42114d39bef093b15067e97e972d348573250b67 100644
--- a/product/ERP5/Document/SolverProcess.py
+++ b/product/ERP5/Document/SolverProcess.py
@@ -138,6 +138,7 @@ class SolverProcess(XMLObject, ActiveProcess):
       Start solving
     """
     for solver in self.contentValues(portal_type=self.getPortalObject().getPortalTargetSolverTypeList()):
+      solver.startSolving()
       solver.activate(active_process=self).solve()