diff --git a/.github/workflows/msvc-code-analysis.yml b/.github/workflows/msvc-code-analysis.yml
index 66b47d479f3..3892838112f 100644
--- a/.github/workflows/msvc-code-analysis.yml
+++ b/.github/workflows/msvc-code-analysis.yml
@@ -15,7 +15,7 @@ jobs:
         uses: actions/checkout@v2
 
       - name: Configure CMake
-        run: cmake -B ${{ env.build }} -DCMAKE_BUILD_TYPE=${{ env.config }} -DOGS_BUILD_PROCESS_TH2M=OFF -DOGS_USE_UNITY_BUILDS=OFF -DOGS_BUILD_TESTING=OFF -DOGS_ENABLE_ELEMENT_PRISM=OFF -DOGS_ENABLE_ELEMENT_PYRAMID=OFF -DOGS_MAX_ELEMENT_DIM=2
+        run: cmake -B ${{ env.build }} -DCMAKE_BUILD_TYPE=${{ env.config }} -DOGS_USE_UNITY_BUILDS=OFF -DOGS_BUILD_TESTING=OFF -DOGS_ENABLE_ELEMENT_PRISM=OFF -DOGS_ENABLE_ELEMENT_PYRAMID=OFF -DOGS_MAX_ELEMENT_DIM=2
 
       # Build is not required unless generated source files are used
       # - name: Build CMake
diff --git a/MeshLib/IO/Legacy/MeshIO.cpp b/MeshLib/IO/Legacy/MeshIO.cpp
index faf2e8b7f3d..898d2741049 100644
--- a/MeshLib/IO/Legacy/MeshIO.cpp
+++ b/MeshLib/IO/Legacy/MeshIO.cpp
@@ -29,15 +29,20 @@
 
 namespace
 {
-std::size_t readMaterialID(std::istream& in)
+int readMaterialID(std::istream& in)
 {
     unsigned index;
     unsigned material_id;
-    if (!(in >> index >> material_id))
+
+    if (!(in >> index >> material_id) ||
+        material_id > static_cast<unsigned>(std::numeric_limits<int>::max()))
     {
-        return std::numeric_limits<std::size_t>::max();
+        // If read incorrectly or the material_id is not safely convertible to
+        // int.
+        return std::numeric_limits<int>::max();
     }
-    return material_id;
+    // Safe conversion was checked above.
+    return static_cast<int>(material_id);
 }
 
 MeshLib::Element* readElement(std::istream& in,
@@ -289,7 +294,7 @@ MeshLib::Mesh* MeshIO::loadMeshFromFile(const std::string& file_name)
     {
         std::vector<MeshLib::Node*> nodes;
         std::vector<MeshLib::Element*> elements;
-        std::vector<std::size_t> materials;
+        std::vector<int> materials;
 
         while (!in.eof())
         {
diff --git a/MeshToolsLib/ZeroMeshFieldDataByMaterialIDs.cpp b/MeshToolsLib/ZeroMeshFieldDataByMaterialIDs.cpp
index d36aee77c28..f1644372e4d 100644
--- a/MeshToolsLib/ZeroMeshFieldDataByMaterialIDs.cpp
+++ b/MeshToolsLib/ZeroMeshFieldDataByMaterialIDs.cpp
@@ -81,7 +81,7 @@ void zeroMeshFieldDataByMaterialIDs(
                 std::transform(element_ip_data_offsets.begin(),
                                element_ip_data_offsets.end(),
                                element_ip_data_offsets.begin(),
-                               [n = n_components](double const v)
+                               [n = n_components](std::size_t const v)
                                { return v / n; });
             }
 
diff --git a/NumLib/StaggeredCoupling/CreateStaggeredCoupling.h b/NumLib/StaggeredCoupling/CreateStaggeredCoupling.h
index e533dbccc3d..eb4efc471f8 100644
--- a/NumLib/StaggeredCoupling/CreateStaggeredCoupling.h
+++ b/NumLib/StaggeredCoupling/CreateStaggeredCoupling.h
@@ -12,6 +12,7 @@
 #pragma once
 
 #include <memory>
+#include <string>
 #include <vector>
 
 namespace BaseLib
diff --git a/Tests/Data/TH2M/H2M/Liakopoulos/liakopoulos_TH2M.prj b/Tests/Data/TH2M/H2M/Liakopoulos/liakopoulos_TH2M.prj
index 67887389f06..fe492560c1e 100644
--- a/Tests/Data/TH2M/H2M/Liakopoulos/liakopoulos_TH2M.prj
+++ b/Tests/Data/TH2M/H2M/Liakopoulos/liakopoulos_TH2M.prj
@@ -200,7 +200,7 @@
                     <type>PerComponentDeltaX</type>
                     <norm_type>NORM2</norm_type>
                     <abstols>1e-15 1e-15 1e-05 1e-05 1.e-05</abstols>
-                    <reltols>1e-12 1e-12 1e-15 1e-10 1.e-10</reltols>
+                    <reltols>1e-12 1e-11 1e-15 1e-10 1.e-10</reltols>
                 </convergence_criterion>
                 <time_discretization>
                     <type>BackwardEuler</type>
diff --git a/pyproject.toml b/pyproject.toml
index 8f0af55e70c..113abb2a11c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -78,7 +78,6 @@ environment-pass = [
 # maybe this should be moved to CMake logic, i.e. disabling both features on win
 [tool.cibuildwheel.windows.config-settings]
 "cmake.define.OGS_USE_MFRONT" = "OFF"
-"cmake.define.OGS_BUILD_PROCESS_TH2M" = "OFF"
 # Generator needs to be set here, CMAKE_GENERATOR env var does not work.
 # Ninja generator does not select  the host64 compiler.
 "cmake.args" = "-G;Visual Studio 16 2019;--preset;wheel"
diff --git a/scripts/ci/jobs/build-gui-win.yml b/scripts/ci/jobs/build-gui-win.yml
index 84ea090a82c..5a8e2b4ded0 100644
--- a/scripts/ci/jobs/build-gui-win.yml
+++ b/scripts/ci/jobs/build-gui-win.yml
@@ -5,7 +5,7 @@ build gui win:
   rules:
     - if: '$CI_COMMIT_BRANCH == "master"'
       variables:
-        ADDITIONAL_CMAKE_ARGS: " -DOGS_BUILD_CLI=ON -DOGS_BUILD_PROCESS_TH2M=OFF"
+        ADDITIONAL_CMAKE_ARGS: " -DOGS_BUILD_CLI=ON"
         BUILD_TESTS: "false"
         BUILD_CTEST: "false"
     - if: $CI_COMMIT_BRANCH =~ /^v[0-9]\.[0-9]\.[0-9]/
diff --git a/scripts/ci/jobs/build-win.yml b/scripts/ci/jobs/build-win.yml
index c4e687de1c6..f84ade6b177 100644
--- a/scripts/ci/jobs/build-win.yml
+++ b/scripts/ci/jobs/build-win.yml
@@ -5,12 +5,11 @@ build win:
   variables:
     CHECK_WARNINGS: "true"
     CMAKE_PRESET: release
-    # TODO: temporary switched off TH2M
     CMAKE_ARGS: >-
       -DOGS_CI_TESTRUNNER_REPEAT=1
-      -DOGS_BUILD_PROCESS_TH2M=OFF
       -DOGS_USE_PIP=ON
       -DOGS_USE_MKL=ON
+      -DOGS_USE_UNITY_BUILDS=OFF
 
 build win msvc:
   extends: