diff --git a/CMakeLists.txt b/CMakeLists.txt
index 18107bcf44c..f229c8df619 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -326,7 +326,12 @@ add_subdirectory(src/ConvertInputFormat)
 
 if(BUILD_FORTRAN)
   include(CMakeAddFortranSubdirectory)
-  include(cmake/Fortran.cmake)
+  if (UNIX)
+    # Define a top-level target `fortran_project_options`
+    # It seems that CMakeAddFortranSubdirectory] doesn't know about the target `fortran_project_option` on Windows only.
+    # On Unix it is seen and detected as multiple targets defined with the same name (CMP0002)
+    include(cmake/Fortran.cmake)
+  endif()
   cmake_add_fortran_subdirectory(
     src/ExpandObjects
     PROJECT ExpandObjects
diff --git a/src/AppGPostProcess/CMakeLists.txt b/src/AppGPostProcess/CMakeLists.txt
index f47b9310e99..b73311344ef 100644
--- a/src/AppGPostProcess/CMakeLists.txt
+++ b/src/AppGPostProcess/CMakeLists.txt
@@ -16,7 +16,11 @@ set(SKIP_BUILD_RPATH TRUE)
 add_executable(AppGPostProcess ${SRC})
 set_target_properties(AppGPostProcess PROPERTIES FOLDER Auxiliary)
 
-include("${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/Fortran.cmake")
+if(NOT UNIX)  # Defined as top-level target on Unix only
+  include("${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/Fortran.cmake")
+endif()
+get_target_property(F_INTERFACE_COMPILE_FLAGS fortran_project_options INTERFACE_COMPILE_OPTIONS)
+message(DEBUG "AppGPostProcess: F_INTERFACE_COMPILE_FLAGS=${F_INTERFACE_COMPILE_FLAGS}")
 target_link_libraries(AppGPostProcess PRIVATE fortran_project_options)
 
 install(TARGETS AppGPostProcess DESTINATION PostProcess)
diff --git a/src/Basement/CMakeLists.txt b/src/Basement/CMakeLists.txt
index d0f65493574..ee37d3605e3 100644
--- a/src/Basement/CMakeLists.txt
+++ b/src/Basement/CMakeLists.txt
@@ -58,7 +58,11 @@ add_executable(Basement ${SRC})
 target_compile_options(Basement PRIVATE -O1)
 set_target_properties(Basement PROPERTIES FOLDER Auxiliary)
 
-include("${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/Fortran.cmake")
+if(NOT UNIX)  # Defined as top-level target on Unix only
+  include("${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/Fortran.cmake")
+endif()
+get_target_property(F_INTERFACE_COMPILE_FLAGS fortran_project_options INTERFACE_COMPILE_OPTIONS)
+message(DEBUG "Basement: F_INTERFACE_COMPILE_FLAGS=${F_INTERFACE_COMPILE_FLAGS}")
 target_link_libraries(Basement PRIVATE BasementOptions fortran_project_options)
 
 install(TARGETS Basement DESTINATION PreProcess/GrndTempCalc)
diff --git a/src/CalcSoilSurfTemp/CMakeLists.txt b/src/CalcSoilSurfTemp/CMakeLists.txt
index 0dc919aafcf..89bc4f54c29 100644
--- a/src/CalcSoilSurfTemp/CMakeLists.txt
+++ b/src/CalcSoilSurfTemp/CMakeLists.txt
@@ -16,7 +16,11 @@ set(SKIP_BUILD_RPATH TRUE)
 add_executable(CalcSoilSurfTemp ${SRC})
 set_target_properties(CalcSoilSurfTemp PROPERTIES FOLDER Auxiliary)
 
-include("${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/Fortran.cmake")
+if(NOT UNIX)  # Defined as top-level target on Unix only
+  include("${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/Fortran.cmake")
+endif()
+get_target_property(F_INTERFACE_COMPILE_FLAGS fortran_project_options INTERFACE_COMPILE_OPTIONS)
+message(DEBUG "CalcSoilSurfTemp: F_INTERFACE_COMPILE_FLAGS=${F_INTERFACE_COMPILE_FLAGS}")
 target_link_libraries(CalcSoilSurfTemp PRIVATE fortran_project_options)
 
 install(TARGETS CalcSoilSurfTemp DESTINATION PreProcess/CalcSoilSurfTemp)
diff --git a/src/ConvertESOMTR/CMakeLists.txt b/src/ConvertESOMTR/CMakeLists.txt
index 64e6355a295..49bb8cf2394 100644
--- a/src/ConvertESOMTR/CMakeLists.txt
+++ b/src/ConvertESOMTR/CMakeLists.txt
@@ -16,7 +16,11 @@ set(SKIP_BUILD_RPATH TRUE)
 add_executable(convertESOMTR ${SRC})
 set_target_properties(convertESOMTR PROPERTIES FOLDER Auxiliary)
 
-include("${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/Fortran.cmake")
+if(NOT UNIX)  # Defined as top-level target on Unix only
+  include("${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/Fortran.cmake")
+endif()
+get_target_property(F_INTERFACE_COMPILE_FLAGS fortran_project_options INTERFACE_COMPILE_OPTIONS)
+message(DEBUG "ConvertESOMTR: F_INTERFACE_COMPILE_FLAGS=${F_INTERFACE_COMPILE_FLAGS}")
 target_link_libraries(convertESOMTR PRIVATE fortran_project_options)
 
 install(TARGETS convertESOMTR DESTINATION "PostProcess/convertESOMTRpgm/")
diff --git a/src/ExpandObjects/CMakeLists.txt b/src/ExpandObjects/CMakeLists.txt
index ff6e555e8cc..768c6805cbf 100644
--- a/src/ExpandObjects/CMakeLists.txt
+++ b/src/ExpandObjects/CMakeLists.txt
@@ -22,7 +22,11 @@ set(SKIP_BUILD_RPATH TRUE)
 add_executable(ExpandObjects ${SRC})
 target_link_libraries(ExpandObjects PRIVATE fortran_project_options)
 
-include("${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/Fortran.cmake")
+if(NOT UNIX)  # Defined as top-level target on Unix only
+  include("${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/Fortran.cmake")
+endif()
+get_target_property(F_INTERFACE_COMPILE_FLAGS fortran_project_options INTERFACE_COMPILE_OPTIONS)
+message(DEBUG "ExpandObjects: F_INTERFACE_COMPILE_FLAGS=${F_INTERFACE_COMPILE_FLAGS}")
 set_target_properties(ExpandObjects PROPERTIES FOLDER Auxiliary)
 
 install(TARGETS ExpandObjects DESTINATION "./")
diff --git a/src/HVAC-Diagram/CMakeLists.txt b/src/HVAC-Diagram/CMakeLists.txt
index 53ec763feb0..369fe8658c4 100644
--- a/src/HVAC-Diagram/CMakeLists.txt
+++ b/src/HVAC-Diagram/CMakeLists.txt
@@ -16,7 +16,11 @@ set(SKIP_BUILD_RPATH true)
 add_executable(HVAC-Diagram ${SRC})
 set_target_properties(HVAC-Diagram PROPERTIES FOLDER Auxiliary)
 
-include("${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/Fortran.cmake")
+if(NOT UNIX)  # Defined as top-level target on Unix only
+  include("${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/Fortran.cmake")
+endif()
+get_target_property(F_INTERFACE_COMPILE_FLAGS fortran_project_options INTERFACE_COMPILE_OPTIONS)
+message(DEBUG "HVAC-Diagram: F_INTERFACE_COMPILE_FLAGS=${F_INTERFACE_COMPILE_FLAGS}")
 target_link_libraries(HVAC-Diagram PRIVATE fortran_project_options)
 
 if(NOT CMAKE_Fortran_COMPILER MATCHES "ifort")
diff --git a/src/ParametricPreprocessor/CMakeLists.txt b/src/ParametricPreprocessor/CMakeLists.txt
index 3df9a308f4b..28369fa5157 100644
--- a/src/ParametricPreprocessor/CMakeLists.txt
+++ b/src/ParametricPreprocessor/CMakeLists.txt
@@ -16,7 +16,11 @@ set(SKIP_BUILD_RPATH true)
 add_executable(ParametricPreprocessor ${SRC})
 set_target_properties(ParametricPreprocessor PROPERTIES FOLDER Auxiliary)
 
-include("${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/Fortran.cmake")
+if(NOT UNIX)  # Defined as top-level target on Unix only
+  include("${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/Fortran.cmake")
+endif()
+get_target_property(F_INTERFACE_COMPILE_FLAGS fortran_project_options INTERFACE_COMPILE_OPTIONS)
+message(DEBUG "ParametricPreprocessor: F_INTERFACE_COMPILE_FLAGS=${F_INTERFACE_COMPILE_FLAGS}")
 target_link_libraries(ParametricPreprocessor PRIVATE fortran_project_options)
 
 install(TARGETS ParametricPreprocessor DESTINATION PreProcess/ParametricPreprocessor)
diff --git a/src/ReadVars/CMakeLists.txt b/src/ReadVars/CMakeLists.txt
index 507b3285426..068a8b01573 100644
--- a/src/ReadVars/CMakeLists.txt
+++ b/src/ReadVars/CMakeLists.txt
@@ -16,7 +16,11 @@ set(SKIP_BUILD_RPATH true)
 add_executable(ReadVarsESO ${SRC})
 set_target_properties(ReadVarsESO PROPERTIES FOLDER Auxiliary)
 
-include("${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/Fortran.cmake")
+if(NOT UNIX)  # Defined as top-level target on Unix only
+  include("${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/Fortran.cmake")
+endif()
+get_target_property(F_INTERFACE_COMPILE_FLAGS fortran_project_options INTERFACE_COMPILE_OPTIONS)
+message(DEBUG "ReadVars: F_INTERFACE_COMPILE_FLAGS=${F_INTERFACE_COMPILE_FLAGS}")
 target_link_libraries(ReadVarsESO PRIVATE fortran_project_options)
 
 install(TARGETS ReadVarsESO DESTINATION PostProcess)
diff --git a/src/Slab/CMakeLists.txt b/src/Slab/CMakeLists.txt
index c1e82c60eff..9fbc9fdd8b7 100644
--- a/src/Slab/CMakeLists.txt
+++ b/src/Slab/CMakeLists.txt
@@ -28,7 +28,11 @@ set(SKIP_BUILD_RPATH true)
 add_executable(Slab ${SRC})
 set_target_properties(Slab PROPERTIES FOLDER Auxiliary)
 
-include("${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/Fortran.cmake")
+if(NOT UNIX)  # Defined as top-level target on Unix only
+  include("${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/Fortran.cmake")
+endif()
+get_target_property(F_INTERFACE_COMPILE_FLAGS fortran_project_options INTERFACE_COMPILE_OPTIONS)
+message(DEBUG "Slab: F_INTERFACE_COMPILE_FLAGS=${F_INTERFACE_COMPILE_FLAGS}")
 target_link_libraries(Slab PRIVATE fortran_project_options)
 
 install(TARGETS Slab DESTINATION PreProcess/GrndTempCalc)
diff --git a/src/Transition/CMakeLists.txt b/src/Transition/CMakeLists.txt
index f74075075e0..14d4a5e6553 100644
--- a/src/Transition/CMakeLists.txt
+++ b/src/Transition/CMakeLists.txt
@@ -29,7 +29,11 @@ add_library(TransitionLib STATIC ${LIB_SRC})
 target_include_directories(TransitionLib PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
 target_compile_options(TransitionLib PUBLIC -fbounds-check)
 
-include("${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/Fortran.cmake")
+if(NOT UNIX)  # Defined as top-level target on Unix only
+  include("${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/Fortran.cmake")
+endif()
+get_target_property(F_INTERFACE_COMPILE_FLAGS fortran_project_options INTERFACE_COMPILE_OPTIONS)
+message(DEBUG "Transition: F_INTERFACE_COMPILE_FLAGS=${F_INTERFACE_COMPILE_FLAGS}")
 target_link_libraries(TransitionLib PUBLIC fortran_project_options) # ffree-line-length-none
 
 set(VERSIONS