diff --git a/src/cpp/benders/benders_core/BendersBase.cpp b/src/cpp/benders/benders_core/BendersBase.cpp
index 5f8f3b51e..311c10aff 100644
--- a/src/cpp/benders/benders_core/BendersBase.cpp
+++ b/src/cpp/benders/benders_core/BendersBase.cpp
@@ -1,4 +1,5 @@
 #include "antares-xpansion/benders/benders_core/BendersBase.h"
+#include <fmt/format.h>
 
 #include <memory>
 #include <mutex>
@@ -8,6 +9,7 @@
 #include "antares-xpansion/benders/benders_core/LastIterationPrinter.h"
 #include "antares-xpansion/benders/benders_core/LastIterationReader.h"
 #include "antares-xpansion/benders/benders_core/LastIterationWriter.h"
+#include "antares-xpansion/benders/benders_core/ProblemFormatStream.h"
 #include "antares-xpansion/xpansion_interfaces/LogUtils.h"
 #include "antares-xpansion/helpers/solver_utils.h"
 
diff --git a/src/cpp/benders/benders_core/ProblemFormatStream.cpp b/src/cpp/benders/benders_core/ProblemFormatStream.cpp
index 30429b828..d7579bf52 100644
--- a/src/cpp/benders/benders_core/ProblemFormatStream.cpp
+++ b/src/cpp/benders/benders_core/ProblemFormatStream.cpp
@@ -6,10 +6,10 @@ auto fmt::formatter<ProblemsFormat>::format(ProblemsFormat problems_format,
   string_view result = "Unknown";
   switch (problems_format) {
     case ProblemsFormat::MPS_FILE:
-      result = "MPS_FILE";
+      result = "MPS";
       break;
     case ProblemsFormat::SAVED_FILE:
-      result = "SAVED_FILE";
+      result = "SAVED";
       break;
     default:
       result = "Unknown";
diff --git a/src/cpp/benders/benders_core/include/antares-xpansion/benders/benders_core/BendersBase.h b/src/cpp/benders/benders_core/include/antares-xpansion/benders/benders_core/BendersBase.h
index 3a8c90da8..e814c7386 100644
--- a/src/cpp/benders/benders_core/include/antares-xpansion/benders/benders_core/BendersBase.h
+++ b/src/cpp/benders/benders_core/include/antares-xpansion/benders/benders_core/BendersBase.h
@@ -16,7 +16,6 @@
 #include "WorkerMaster.h"
 #include "antares-xpansion/helpers/Timer.h"
 #include "antares-xpansion/xpansion_interfaces/ILogger.h"
-#include "antares-xpansion/xpansion_interfaces/OutputWriter.h"
 #include "common.h"
 /**
  * std execution policies don't share a base type so we can't just select
diff --git a/src/cpp/benders/benders_core/include/antares-xpansion/benders/benders_core/ProblemFormatStream.h b/src/cpp/benders/benders_core/include/antares-xpansion/benders/benders_core/ProblemFormatStream.h
index 401593c63..2e4d12831 100644
--- a/src/cpp/benders/benders_core/include/antares-xpansion/benders/benders_core/ProblemFormatStream.h
+++ b/src/cpp/benders/benders_core/include/antares-xpansion/benders/benders_core/ProblemFormatStream.h
@@ -10,10 +10,10 @@ inline std::ostream &operator<<(std::ostream &stream,
                                 ProblemsFormat const &rhs) {
   switch (rhs) {
     case ProblemsFormat::MPS_FILE:
-      stream << "MPS_FILE";
+      stream << "MPS";
       break;
     case ProblemsFormat::SAVED_FILE:
-      stream << "SAVED_FILE";
+      stream << "SAVED";
       break;
     default:
       stream << "Unknown";
diff --git a/src/cpp/benders/benders_core/include/antares-xpansion/benders/benders_core/StartUp.h b/src/cpp/benders/benders_core/include/antares-xpansion/benders/benders_core/StartUp.h
index 9eaa69eb5..48726359b 100644
--- a/src/cpp/benders/benders_core/include/antares-xpansion/benders/benders_core/StartUp.h
+++ b/src/cpp/benders/benders_core/include/antares-xpansion/benders/benders_core/StartUp.h
@@ -4,9 +4,9 @@
 
 #pragma once
 
-#include "antares-xpansion/xpansion_interfaces/ILogger.h"
-#include "antares-xpansion/xpansion_interfaces/OutputWriter.h"
 #include "SimulationOptions.h"
+#include "antares-xpansion/benders/output/OutputWriter.h"
+#include "antares-xpansion/xpansion_interfaces/ILogger.h"
 namespace Benders {
 
 class StartUp {
diff --git a/src/cpp/benders/benders_core/include/antares-xpansion/benders/benders_core/Worker.h b/src/cpp/benders/benders_core/include/antares-xpansion/benders/benders_core/Worker.h
index 7bdf3e432..4c016d512 100644
--- a/src/cpp/benders/benders_core/include/antares-xpansion/benders/benders_core/Worker.h
+++ b/src/cpp/benders/benders_core/include/antares-xpansion/benders/benders_core/Worker.h
@@ -3,9 +3,9 @@
 #include <filesystem>
 
 #include "SolverIO.h"
+#include "antares-xpansion/benders/output/OutputWriter.h"
 #include "antares-xpansion/multisolver_interface/Solver.h"
 #include "antares-xpansion/xpansion_interfaces/ILogger.h"
-#include "antares-xpansion/xpansion_interfaces/OutputWriter.h"
 #include "common.h"
 
 /*!
diff --git a/src/cpp/benders/factories/BendersFactory.cpp b/src/cpp/benders/factories/BendersFactory.cpp
index 17f00b5c8..4c08b6365 100644
--- a/src/cpp/benders/factories/BendersFactory.cpp
+++ b/src/cpp/benders/factories/BendersFactory.cpp
@@ -1,12 +1,15 @@
 
 #include "antares-xpansion/benders/factories/BendersFactory.h"
 
+#include <fmt/format.h>
+
 #include <filesystem>
 
 #include "antares-xpansion/benders/benders_by_batch/BendersByBatch.h"
 #include "antares-xpansion/benders/benders_core/CouplingMapGenerator.h"
 #include "antares-xpansion/benders/benders_core/MasterUpdate.h"
 #include "antares-xpansion/benders/benders_core/StartUp.h"
+#include "antares-xpansion/benders/benders_core/ProblemFormatStream.h"
 #include "antares-xpansion/benders/benders_mpi/BendersMpiOuterLoop.h"
 #include "antares-xpansion/benders/benders_mpi/OuterLoopBenders.h"
 #include "antares-xpansion/benders/factories/LoggerFactories.h"
@@ -121,6 +124,7 @@ void BendersMainFactory::SetupLoggerAndOutputWriter(
   writer_->write_log_level(options_.LOG_LEVEL);
   writer_->write_master_name(options_.MASTER_NAME);
   writer_->write_solver_name(options_.SOLVER_NAME);
+  writer_->WriteProblemFormat(fmt::format("{}", options_.PROBLEMS_FORMAT));
 }
 
 bool BendersMainFactory::isCriterionListEmpty() const {
diff --git a/src/cpp/benders/factories/WriterFactories.cpp b/src/cpp/benders/factories/WriterFactories.cpp
index 054adcf69..dd2ed5916 100644
--- a/src/cpp/benders/factories/WriterFactories.cpp
+++ b/src/cpp/benders/factories/WriterFactories.cpp
@@ -3,7 +3,6 @@
 #include "antares-xpansion/benders/factories/WriterFactories.h"
 
 #include "antares-xpansion/benders/output/JsonWriter.h"
-#include "antares-xpansion/xpansion_interfaces/OutputWriter.h"
 #include "antares-xpansion/benders/output/VoidWriter.h"
 #include "antares-xpansion/benders/benders_core/common.h"
 
diff --git a/src/cpp/benders/factories/include/antares-xpansion/benders/factories/WriterFactories.h b/src/cpp/benders/factories/include/antares-xpansion/benders/factories/WriterFactories.h
index 16778630e..3c3ba0c35 100644
--- a/src/cpp/benders/factories/include/antares-xpansion/benders/factories/WriterFactories.h
+++ b/src/cpp/benders/factories/include/antares-xpansion/benders/factories/WriterFactories.h
@@ -5,7 +5,7 @@
 #include <filesystem>
 #include <string>
 
-#include "antares-xpansion/xpansion_interfaces/OutputWriter.h"
+#include "antares-xpansion/benders/output/OutputWriter.h"
 
 Writer build_void_writer();
 
diff --git a/src/cpp/benders/output/CMakeLists.txt b/src/cpp/benders/output/CMakeLists.txt
index 3c5daff0f..24c52a2bf 100644
--- a/src/cpp/benders/output/CMakeLists.txt
+++ b/src/cpp/benders/output/CMakeLists.txt
@@ -13,6 +13,7 @@ target_sources(output_core PRIVATE
         ${CMAKE_CURRENT_SOURCE_DIR}/JsonWriter.cpp
         include/antares-xpansion/benders/output/VoidWriter.h
         include/antares-xpansion/benders/output/JsonWriter.h
+        include/antares-xpansion/benders/output/OutputWriter.h
 )
 
 target_include_directories(output_core
diff --git a/src/cpp/benders/output/JsonWriter.cpp b/src/cpp/benders/output/JsonWriter.cpp
index 5ef774afc..fb331bb95 100644
--- a/src/cpp/benders/output/JsonWriter.cpp
+++ b/src/cpp/benders/output/JsonWriter.cpp
@@ -170,4 +170,7 @@ void JsonWriter::WriteProblem(const ProblemData &problem_data) {
   _output[ERROR_C][PROBLEMPATH_C] = problem_data.path.string();
   _output[ERROR_C][PROBLEM_STATUS_C] = problem_data.status;
 }
+void JsonWriter::WriteProblemFormat(const std::string format) {
+  _output[OPTIONS_C][PROBLEM_FORMAT_C] = format;
+}
 }  // namespace Output
\ No newline at end of file
diff --git a/src/cpp/benders/output/VoidWriter.cpp b/src/cpp/benders/output/VoidWriter.cpp
index ec694fe0a..1931ee70c 100644
--- a/src/cpp/benders/output/VoidWriter.cpp
+++ b/src/cpp/benders/output/VoidWriter.cpp
@@ -68,5 +68,6 @@ std::string VoidWriter::solution_status() const { return ""; }
 void VoidWriter::WriteProblem(const ProblemData &problem_data) {
   // keep this method empty
 }
+void VoidWriter::WriteProblemFormat(const std::string format) {}
 
 }  // namespace Output
\ No newline at end of file
diff --git a/src/cpp/benders/output/include/antares-xpansion/benders/output/JsonWriter.h b/src/cpp/benders/output/include/antares-xpansion/benders/output/JsonWriter.h
index 7bc84169a..911f480cc 100644
--- a/src/cpp/benders/output/include/antares-xpansion/benders/output/JsonWriter.h
+++ b/src/cpp/benders/output/include/antares-xpansion/benders/output/JsonWriter.h
@@ -6,8 +6,8 @@
 #include <filesystem>
 #include <fstream>
 
+#include "antares-xpansion/benders/output/OutputWriter.h"
 #include "antares-xpansion/xpansion_interfaces/Clock.h"
-#include "antares-xpansion/xpansion_interfaces/OutputWriter.h"
 
 namespace Output {
 
@@ -79,5 +79,6 @@ class JsonWriter : public OutputWriter {
   void write_duration(const double duration) override;
   std::string solution_status() const override;
   void WriteProblem(const ProblemData &problem_data) override;
+  void WriteProblemFormat(const std::string format) override;
 };
 }  // namespace Output
\ No newline at end of file
diff --git a/src/cpp/xpansion_interfaces/include/antares-xpansion/xpansion_interfaces/OutputWriter.h b/src/cpp/benders/output/include/antares-xpansion/benders/output/OutputWriter.h
similarity index 96%
rename from src/cpp/xpansion_interfaces/include/antares-xpansion/xpansion_interfaces/OutputWriter.h
rename to src/cpp/benders/output/include/antares-xpansion/benders/output/OutputWriter.h
index c474496a0..9e7ccb8d1 100644
--- a/src/cpp/xpansion_interfaces/include/antares-xpansion/xpansion_interfaces/OutputWriter.h
+++ b/src/cpp/benders/output/include/antares-xpansion/benders/output/OutputWriter.h
@@ -26,7 +26,9 @@ const std::string ANTARES_C("antares"), VERSION_C("version"),
     SOLVER_NAME_C("SOLVER_NAME"), PROBLEMNAME_C("problem_name"),
     PROBLEMPATH_C("problem_path"),
     CUMULATIVE_NUMBER_OF_SUBPROBLEM_RESOLVED_C(
-        "cumulative_number_of_subproblem_resolutions");
+        "cumulative_number_of_subproblem_resolutions"),
+    PROBLEM_FORMAT_C{"PROBLEM_FORMAT"}
+;
 struct CandidateData {
   std::string name;
   double invest;
@@ -126,6 +128,7 @@ class OutputWriter {
   virtual void write_duration(const double duration) = 0;
   virtual std::string solution_status() const = 0;
   virtual void WriteProblem(const ProblemData &problem_data) = 0;
+  virtual void WriteProblemFormat(const std::string format) = 0;
 };
 }  // namespace Output
 using Writer = std::shared_ptr<Output::OutputWriter>;
\ No newline at end of file
diff --git a/src/cpp/benders/output/include/antares-xpansion/benders/output/VoidWriter.h b/src/cpp/benders/output/include/antares-xpansion/benders/output/VoidWriter.h
index 08c170cb8..861a1b3fc 100644
--- a/src/cpp/benders/output/include/antares-xpansion/benders/output/VoidWriter.h
+++ b/src/cpp/benders/output/include/antares-xpansion/benders/output/VoidWriter.h
@@ -1,8 +1,7 @@
 
 #pragma once
 
-#include "antares-xpansion/xpansion_interfaces/OutputWriter.h"
-
+#include "antares-xpansion/benders/output/OutputWriter.h"
 namespace Output {
 /*!
  * \class VoidWriter
@@ -71,5 +70,6 @@ class VoidWriter : public OutputWriter {
   void write_duration(const double duration) override;
   std::string solution_status() const override;
   void WriteProblem(const ProblemData &problem_data) override;
+  void WriteProblemFormat(const std::string format) override;
 };
 }  // namespace Output
\ No newline at end of file
diff --git a/src/cpp/sensitivity/CMakeLists.txt b/src/cpp/sensitivity/CMakeLists.txt
index a5b3c5b5a..502dcb0a6 100644
--- a/src/cpp/sensitivity/CMakeLists.txt
+++ b/src/cpp/sensitivity/CMakeLists.txt
@@ -30,9 +30,12 @@ target_include_directories(sensitivity_core
         $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/private>
 )
 
+find_package(fmt REQUIRED)
 target_link_libraries(sensitivity_core
         PUBLIC
         antaresXpansion::logger_lib
+        PRIVATE
+        fmt::fmt
 )
 
 add_library(${PROJECT_NAME}::sensitivity_core ALIAS sensitivity_core)
\ No newline at end of file
diff --git a/src/cpp/sensitivity/SensitivityInputReader.cpp b/src/cpp/sensitivity/SensitivityInputReader.cpp
index e70f0a485..0596cee55 100644
--- a/src/cpp/sensitivity/SensitivityInputReader.cpp
+++ b/src/cpp/sensitivity/SensitivityInputReader.cpp
@@ -1,13 +1,16 @@
 #include "antares-xpansion/sensitivity/SensitivityInputReader.h"
 
+#include <fmt/format.h>
+
 #include <boost/algorithm/string/trim.hpp>
 #include <fstream>
 #include <utility>
 
-#include "antares-xpansion/xpansion_interfaces/LogUtils.h"
-#include "antares-xpansion/xpansion_interfaces/OutputWriter.h"
-#include "antares-xpansion/benders/benders_core/common.h"
+#include "antares-xpansion/benders/benders_core/ProblemFormat.h"
+#include "antares-xpansion/benders/benders_core/ProblemFormatStream.h"
+#include "antares-xpansion/benders/output/OutputWriter.h"
 #include "antares-xpansion/multisolver_interface/SolverFactory.h"
+#include "antares-xpansion/xpansion_interfaces/LogUtils.h"
 
 const std::string EPSILON_C("epsilon");
 const std::string CAPEX_C("capex");
@@ -19,8 +22,8 @@ Json::Value read_json(const std::filesystem::path &json_file_path) {
   if (json_file.good()) {
     json_file >> json_data;
   } else {
-    throw std::runtime_error(LOGLOCATION +
-                             "unable to open : " + json_file_path.string());
+    throw std::runtime_error(fmt::format("{}: unable to open : {}",
+                                         LOGLOCATION, json_file_path.string()));
   }
   return json_data;
 }
@@ -45,9 +48,9 @@ std::vector<std::string> SensitivityInputReader::get_projection() const {
   return projection;
 }
 
-SolverAbstract::Ptr SensitivityInputReader::get_last_master() const {
+std::shared_ptr<SolverAbstract> SensitivityInputReader::get_last_master() const {
   SolverFactory factory;
-  SolverAbstract::Ptr last_master;
+  std::shared_ptr<SolverAbstract> last_master;
 
   if (_benders_data[Output::OPTIONS_C]["SOLVER_NAME"].asString() == "COIN") {
     last_master = factory.create_solver("CBC");
@@ -58,13 +61,25 @@ SolverAbstract::Ptr SensitivityInputReader::get_last_master() const {
   last_master->set_threads(1);
   last_master->set_output_log_level(
       _benders_data[Output::OPTIONS_C]["LOG_LEVEL"].asInt());
-  last_master->read_prob_mps(_last_master_path);
+  auto problem_format = _benders_data[Output::OPTIONS_C][Output::PROBLEM_FORMAT_C].asString();
+  auto format = problem_format.empty() ? ProblemsFormat::MPS_FILE : problemsFormatFromString(problem_format);
+  switch (format) {
+    case ProblemsFormat::MPS_FILE:
+      last_master->read_prob_mps(_last_master_path);
+      break;
+    case ProblemsFormat::SAVED_FILE:
+      last_master->restore_prob(_last_master_path);
+      break;
+    default:
+      throw std::runtime_error(fmt::format("{}: unsupported format : {}",
+                                           LOGLOCATION, format));
+  }
   return last_master;
 }
 
 std::map<std::string, std::pair<double, double>>
 SensitivityInputReader::get_candidates_bounds(
-    SolverAbstract::Ptr last_master,
+    SolverAbstract *last_master,
     const std::map<std::string, int> &name_to_id) const {
   std::map<std::string, std::pair<double, double>> candidates_bounds;
 
@@ -145,7 +160,7 @@ SensitivityInputData SensitivityInputReader::get_input_data() const {
   input_data.last_master = get_last_master();
   input_data.basis_file_path = _basis_file_path;
   input_data.candidates_bounds =
-      get_candidates_bounds(input_data.last_master, input_data.name_to_id);
+      get_candidates_bounds(input_data.last_master.get(), input_data.name_to_id);
   input_data.capex = _json_data[CAPEX_C].asBool();
   input_data.projection = get_projection();
   return input_data;
diff --git a/src/cpp/sensitivity/include/antares-xpansion/sensitivity/SensitivityInputReader.h b/src/cpp/sensitivity/include/antares-xpansion/sensitivity/SensitivityInputReader.h
index df9235260..8d2b47b30 100644
--- a/src/cpp/sensitivity/include/antares-xpansion/sensitivity/SensitivityInputReader.h
+++ b/src/cpp/sensitivity/include/antares-xpansion/sensitivity/SensitivityInputReader.h
@@ -11,7 +11,7 @@ struct SensitivityInputData {
   double benders_capex;
   std::map<std::string, double> benders_solution;
   std::map<std::string, int> name_to_id;
-  SolverAbstract::Ptr last_master;
+  std::shared_ptr<SolverAbstract> last_master;
   std::filesystem::path basis_file_path;
   std::map<std::string, std::pair<double, double>> candidates_bounds;
   bool capex;
@@ -37,13 +37,13 @@ class SensitivityInputReader {
   std::filesystem::path _basis_file_path;
   std::filesystem::path _structure_file_path;
 
-  SolverAbstract::Ptr get_last_master() const;
+  std::shared_ptr<SolverAbstract> get_last_master() const;
   double get_best_ub() const;
   double get_benders_capex() const;
   std::map<std::string, double> get_benders_solution() const;
   std::map<std::string, int> get_name_to_id() const;
   std::vector<std::string> get_projection() const;
   std::map<std::string, std::pair<double, double>> get_candidates_bounds(
-      SolverAbstract::Ptr last_master,
+      SolverAbstract *last_master,
       const std::map<std::string, int> &name_to_id) const;
 };
diff --git a/src/cpp/xpansion_interfaces/CMakeLists.txt b/src/cpp/xpansion_interfaces/CMakeLists.txt
index 7e3a0744e..c668b524c 100644
--- a/src/cpp/xpansion_interfaces/CMakeLists.txt
+++ b/src/cpp/xpansion_interfaces/CMakeLists.txt
@@ -12,7 +12,6 @@ target_sources(xpansion_interfaces
         ${CMAKE_CURRENT_SOURCE_DIR}/include/antares-xpansion/xpansion_interfaces/ILogger.h
         ${CMAKE_CURRENT_SOURCE_DIR}/include/antares-xpansion/xpansion_interfaces/IWriterLogger.h
         ${CMAKE_CURRENT_SOURCE_DIR}/include/antares-xpansion/xpansion_interfaces/LogUtils.h
-        ${CMAKE_CURRENT_SOURCE_DIR}/include/antares-xpansion/xpansion_interfaces/OutputWriter.h
         ${CMAKE_CURRENT_SOURCE_DIR}/include/antares-xpansion/xpansion_interfaces/StringManip.h
         ${CMAKE_CURRENT_SOURCE_DIR}/include/antares-xpansion/xpansion_interfaces/Clock.h
 )
diff --git a/src/python/antares_xpansion/config_loader.py b/src/python/antares_xpansion/config_loader.py
index c2759c15c..46c9086eb 100644
--- a/src/python/antares_xpansion/config_loader.py
+++ b/src/python/antares_xpansion/config_loader.py
@@ -694,11 +694,16 @@ def structure_file_path(self):
 
     def last_master_file_path(self):
         # The 'last_iteration' literal is only hard-coded in Worker.cpp, should we introduce a new variable in _config.options_default ?
-        return os.path.join(
+        use_xpress = str(self.options["solver"]).upper() == "XPRESS"
+        base_path = os.path.join(
             self.simulation_lp_path(),
             self._config.options_default["MASTER_NAME"] +
-            "_last_iteration.mps",
-        )
+            "_last_iteration")
+        if use_xpress:
+            base_path += ".svf"
+        else:
+            base_path += ".mps"
+        return base_path
 
     def last_master_basis_path(self):
         return os.path.join(
diff --git a/src/python/antares_xpansion/sensitivity_driver.py b/src/python/antares_xpansion/sensitivity_driver.py
index 8a729f352..8199d4c96 100644
--- a/src/python/antares_xpansion/sensitivity_driver.py
+++ b/src/python/antares_xpansion/sensitivity_driver.py
@@ -2,12 +2,9 @@
     Class to control the sensitivity analysis
 """
 
-import glob
 import os
-import shutil
 import subprocess
 import sys
-import zipfile
 from pathlib import Path
 
 from antares_xpansion.logger import step_logger
@@ -52,7 +49,7 @@ def launch(
         old_cwd = os.getcwd()
         os.chdir(xpansion_simulation_output)
         self.logger.info(f"Current directory is now {os.getcwd()}")
-
+        self.logger.info(f"Launching sensitivity analysis : {self._get_sensitivity_cmd()}")
         returned_l = subprocess.run(
             self._get_sensitivity_cmd(),
             shell=False,
diff --git a/tests/cpp/TestDoubles/WriterStub.h b/tests/cpp/TestDoubles/WriterStub.h
index d34182449..d35003ed7 100644
--- a/tests/cpp/TestDoubles/WriterStub.h
+++ b/tests/cpp/TestDoubles/WriterStub.h
@@ -3,7 +3,6 @@
 //
 
 #pragma once
-#include "antares-xpansion/xpansion_interfaces/OutputWriter.h"
 
 class WriterNOOPStub : public Output::OutputWriter {
  public:
@@ -24,4 +23,5 @@ class WriterNOOPStub : public Output::OutputWriter {
   void write_duration(const double duration) override {}
   std::string solution_status() const override { return std::string(); }
   void WriteProblem(const Output::ProblemData& problem_data) override {}
+  void WriteProblemFormat(const std::string format) override {}
 };
\ No newline at end of file