diff --git a/external/untwine/untwine/windows/mapfile.hpp b/external/untwine/untwine/windows/mapfile.hpp
index abd7dcfbc08..8cbc4b93b20 100644
--- a/external/untwine/untwine/windows/mapfile.hpp
+++ b/external/untwine/untwine/windows/mapfile.hpp
@@ -1,6 +1,6 @@
 #pragma once
 
-#include <Windows.h>
+#include <windows.h>
 #include <io.h>
 #include <fcntl.h>
 
diff --git a/src/analysis/CMakeLists.txt b/src/analysis/CMakeLists.txt
index c633fcd974a..751f0ee52cd 100644
--- a/src/analysis/CMakeLists.txt
+++ b/src/analysis/CMakeLists.txt
@@ -483,6 +483,13 @@ if (WITH_PDAL AND PDAL_2_5_OR_HIGHER)
   include_directories(
     ${CMAKE_SOURCE_DIR}/external/untwine/api
   )
+
+  IF(MSVC)
+    set_source_files_properties(
+      ${CMAKE_SOURCE_DIR}/external/untwine/api/QgisUntwine.cpp
+      PROPERTIES COMPILE_FLAGS "/DUNICODE"
+    )
+  endif()
 endif()
 
 include_directories(SYSTEM ${SPATIALINDEX_INCLUDE_DIR})
diff --git a/src/providers/pdal/CMakeLists.txt b/src/providers/pdal/CMakeLists.txt
index ff970745fd2..05c49ec6cfa 100644
--- a/src/providers/pdal/CMakeLists.txt
+++ b/src/providers/pdal/CMakeLists.txt
@@ -14,6 +14,13 @@ set(PDAL_SRCS
   ${CMAKE_SOURCE_DIR}/external/untwine/api/QgisUntwine.cpp
 )
 
+IF(MSVC)
+  set_source_files_properties(
+    ${CMAKE_SOURCE_DIR}/external/untwine/api/QgisUntwine.cpp
+    PROPERTIES COMPILE_FLAGS "/DUNICODE"
+  )
+endif()
+
 set(PDAL_HDRS
   qgspdalprovider.h
   qgspdalindexingtask.h