diff --git a/CMakePresets.json b/CMakePresets.json
index feb7624772..57be860b38 100644
--- a/CMakePresets.json
+++ b/CMakePresets.json
@@ -12,6 +12,7 @@
             "generator": "NMake Makefiles",
             "hidden": false,
             "binaryDir": "${sourceDir}/build/${presetName}",
+            "toolchainFile": "${sourceDir}/cmake/vc6toolchain.cmake",
             "cacheVariables": {
                 "CMAKE_EXPORT_COMPILE_COMMANDS": "ON",
                 "CMAKE_MSVC_RUNTIME_LIBRARY": "MultiThreaded$<$<CONFIG:Debug>:Debug>DLL",
diff --git a/cmake/config-build.cmake b/cmake/config-build.cmake
index a001e42c59..e8b97c9e10 100644
--- a/cmake/config-build.cmake
+++ b/cmake/config-build.cmake
@@ -61,7 +61,11 @@ if(UNIX)
 endif()
 
 if(RTS_BUILD_OPTION_DEBUG)
-    target_compile_definitions(core_config INTERFACE RTS_DEBUG WWDEBUG DEBUG)
+    if(NOT IS_VS6_BUILD)
+        target_compile_definitions(core_config INTERFACE RTS_DEBUG WWDEBUG DEBUG)
+    else()
+        target_compile_definitions(core_config INTERFACE RTS_DEBUG WWDEBUG)
+    endif()
 else()
     target_compile_definitions(core_config INTERFACE RTS_RELEASE)
 
diff --git a/cmake/vc6toolchain.cmake b/cmake/vc6toolchain.cmake
new file mode 100644
index 0000000000..7f50d7d3dc
--- /dev/null
+++ b/cmake/vc6toolchain.cmake
@@ -0,0 +1,63 @@
+# Setting C++ default compiler flags for VC6 
+
+string(JOIN " " VC6_CXX_FLAGS
+    "/DWIN32"          # Define WIN32 macro
+    "/D_WINDOWS"       # Define _WINDOWS macro
+    "/Zm800"           # Cap precompiled header memory allocation to prevent running out of heap space
+    "/Gd"              # __cdecl calling convention for all functions (C/C++ standard behaviour)
+    "/GR"              # Enable RTTI (Run-Time Type Information, needed for things like dynamic_cast)
+    "/EHs"             # Synchronous C++ exception handling (ISO-standard C++ exception handling)
+    "/EHc"             # Assume extern "C" functions never throw (safe for release)
+)
+string(JOIN " " VC6_CXX_FLAGS_RELEASE
+    "/O2"              # Optimize for speed
+    "/Ob2"             # Inline any suitable function
+    "/Oy"              # Omit frame pointer (smaller/faster code)
+    "/DNDEBUG"
+    "/O2"              # Optimize for speed
+    "/nologo"          # Suppress copyright message
+)
+string(JOIN " " VC6_CXX_FLAGS_DEBUG
+    "/Og /Oi /Gs"      # Optimize for speed (for compatibility)
+    "/Ob2"             # Inline any suitable function (for compatibility)
+    "/Oy-"             # Don't omit frame pointer
+    "/DNDEBUG"         # (for compatibility)
+)
+string(JOIN " " VC6_EXE_LINKER_FLAGS
+    "/machine:IX86"     # Target x86 architecture
+    "/LARGEADDRESSAWARE"# Allow addresses larger than 2 gigabytes"
+)
+string(JOIN " " VC6_EXE_LINKER_FLAGS_RELEASE
+    "/RELEASE"         # Set the checksum in the header and mark as release
+    "/OPT:REF,ICF"     # Remove unreferenced code/data, COMDAT folding
+    "/NOLOGO"          # Suppress linker startup banner
+)
+string(JOIN " " VC6_EXE_LINKER_FLAGS_DEBUG
+    "/DEBUG"           # Generate debug info
+    "/OPT:NOREF,ICF"   # Don't remove unreferenced code/data, COMDAT folding
+)
+set(CMAKE_CXX_FLAGS           "${VC6_CXX_FLAGS}"          CACHE STRING "" FORCE)
+set(CMAKE_CXX_FLAGS_RELEASE   "${VC6_CXX_FLAGS_RELEASE}"  CACHE STRING "" FORCE)
+set(CMAKE_CXX_FLAGS_DEBUG     "${VC6_CXX_FLAGS_DEBUG}"    CACHE STRING "" FORCE)
+set(CMAKE_C_FLAGS             "${VC6_CXX_FLAGS}"          CACHE STRING "" FORCE)
+set(CMAKE_C_FLAGS_RELEASE     "${VC6_CXX_FLAGS_RELEASE}"  CACHE STRING "" FORCE)
+set(CMAKE_C_FLAGS_DEBUG       "${VC6_CXX_FLAGS_DEBUG}"    CACHE STRING "" FORCE)
+
+
+set(CMAKE_EXE_LINKER_FLAGS    "${VC6_EXE_LINKER_FLAGS}" CACHE STRING "" FORCE)
+set(CMAKE_SHARED_LINKER_FLAGS "${VC6_EXE_LINKER_FLAGS}" CACHE STRING "" FORCE)
+set(CMAKE_MODULE_LINKER_FLAGS "${VC6_EXE_LINKER_FLAGS}" CACHE STRING "" FORCE)
+
+set(CMAKE_EXE_LINKER_FLAGS_DEBUG    "${VC6_EXE_LINKER_FLAGS_DEBUG}" CACHE STRING "" FORCE)
+set(CMAKE_SHARED_LINKER_FLAGS_DEBUG "${VC6_EXE_LINKER_FLAGS_DEBUG}" CACHE STRING "" FORCE)
+set(CMAKE_MODULE_LINKER_FLAGS_DEBUG "${VC6_EXE_LINKER_FLAGS_DEBUG}" CACHE STRING "" FORCE)
+
+set(CMAKE_EXE_LINKER_FLAGS_RELEASE    "${VC6_EXE_LINKER_FLAGS_RELEASE}" CACHE STRING "" FORCE)
+set(CMAKE_SHARED_LINKER_FLAGS_RELEASE "${VC6_EXE_LINKER_FLAGS_RELEASE}" CACHE STRING "" FORCE)
+set(CMAKE_SHARED_MODULE_FLAGS_RELEASE "${VC6_EXE_LINKER_FLAGS_RELEASE}" CACHE STRING "" FORCE)
+
+set(CMAKE_STATIC_LINKER_FLAGS "/machine:IX86" CACHE STRING "" FORCE)
+set(CMAKE_STATIC_LINKER_FLAGS_RELEASE "" CACHE STRING "" FORCE)
+set(CMAKE_STATIC_LINKER_FLAGS_DEBUG "" CACHE STRING "" FORCE)
+
+