diff --git a/libcxx/modules/std.compat.cppm.in b/libcxx/modules/std.compat.cppm.in
index 651d6ec7b9fe2..16363711ac762 100644
--- a/libcxx/modules/std.compat.cppm.in
+++ b/libcxx/modules/std.compat.cppm.in
@@ -46,39 +46,48 @@ module;
 #endif
 
 // *** Headers not yet available ***
-#if __has_include(<debugging>)
-#  error "please update the header information for <debugging> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<debugging>)
-#if __has_include(<flat_map>)
-#  error "please update the header information for <flat_map> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<flat_map>)
-#if __has_include(<flat_set>)
-#  error "please update the header information for <flat_set> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<flat_set>)
-#if __has_include(<generator>)
-#  error "please update the header information for <generator> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<generator>)
-#if __has_include(<hazard_pointer>)
-#  error "please update the header information for <hazard_pointer> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<hazard_pointer>)
-#if __has_include(<linalg>)
-#  error "please update the header information for <linalg> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<linalg>)
-#if __has_include(<rcu>)
-#  error "please update the header information for <rcu> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<rcu>)
-#if __has_include(<spanstream>)
-#  error "please update the header information for <spanstream> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<spanstream>)
-#if __has_include(<stacktrace>)
-#  error "please update the header information for <stacktrace> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<stacktrace>)
-#if __has_include(<stdfloat>)
-#  error "please update the header information for <stdfloat> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<stdfloat>)
-#if __has_include(<text_encoding>)
-#  error "please update the header information for <text_encoding> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<text_encoding>)
+//
+// This validation is mainly to aid libc++ developers to add modules for new
+// headers. On Windows the Windows SDK can be in the include path. This SDK
+// contains the MSVC STL headers. This may give false positives when MSVC STL
+// provides a header libc++ has not implemented yet. Therefore this validation
+// is not done on Windows.
+//
+#ifndef _WIN32
+#  if __has_include(<debugging>)
+#    error "please update the header information for <debugging> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<debugging>)
+#  if __has_include(<flat_map>)
+#    error "please update the header information for <flat_map> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<flat_map>)
+#  if __has_include(<flat_set>)
+#    error "please update the header information for <flat_set> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<flat_set>)
+#  if __has_include(<generator>)
+#    error "please update the header information for <generator> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<generator>)
+#  if __has_include(<hazard_pointer>)
+#    error "please update the header information for <hazard_pointer> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<hazard_pointer>)
+#  if __has_include(<linalg>)
+#    error "please update the header information for <linalg> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<linalg>)
+#  if __has_include(<rcu>)
+#    error "please update the header information for <rcu> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<rcu>)
+#  if __has_include(<spanstream>)
+#    error "please update the header information for <spanstream> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<spanstream>)
+#  if __has_include(<stacktrace>)
+#    error "please update the header information for <stacktrace> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<stacktrace>)
+#  if __has_include(<stdfloat>)
+#    error "please update the header information for <stdfloat> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<stdfloat>)
+#  if __has_include(<text_encoding>)
+#    error "please update the header information for <text_encoding> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<text_encoding>)
+#endif // _WIN32
 
 export module std.compat;
 export import std;
diff --git a/libcxx/modules/std.cppm.in b/libcxx/modules/std.cppm.in
index 6ce8e287737b8..3b59c28482b11 100644
--- a/libcxx/modules/std.cppm.in
+++ b/libcxx/modules/std.cppm.in
@@ -168,39 +168,48 @@ module;
 #include <version>
 
 // *** Headers not yet available ***
-#if __has_include(<debugging>)
-#  error "please update the header information for <debugging> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<debugging>)
-#if __has_include(<flat_map>)
-#  error "please update the header information for <flat_map> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<flat_map>)
-#if __has_include(<flat_set>)
-#  error "please update the header information for <flat_set> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<flat_set>)
-#if __has_include(<generator>)
-#  error "please update the header information for <generator> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<generator>)
-#if __has_include(<hazard_pointer>)
-#  error "please update the header information for <hazard_pointer> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<hazard_pointer>)
-#if __has_include(<linalg>)
-#  error "please update the header information for <linalg> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<linalg>)
-#if __has_include(<rcu>)
-#  error "please update the header information for <rcu> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<rcu>)
-#if __has_include(<spanstream>)
-#  error "please update the header information for <spanstream> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<spanstream>)
-#if __has_include(<stacktrace>)
-#  error "please update the header information for <stacktrace> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<stacktrace>)
-#if __has_include(<stdfloat>)
-#  error "please update the header information for <stdfloat> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<stdfloat>)
-#if __has_include(<text_encoding>)
-#  error "please update the header information for <text_encoding> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<text_encoding>)
+//
+// This validation is mainly to aid libc++ developers to add modules for new
+// headers. On Windows the Windows SDK can be in the include path. This SDK
+// contains the MSVC STL headers. This may give false positives when MSVC STL
+// provides a header libc++ has not implemented yet. Therefore this validation
+// is not done on Windows.
+//
+#ifndef _WIN32
+#  if __has_include(<debugging>)
+#    error "please update the header information for <debugging> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<debugging>)
+#  if __has_include(<flat_map>)
+#    error "please update the header information for <flat_map> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<flat_map>)
+#  if __has_include(<flat_set>)
+#    error "please update the header information for <flat_set> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<flat_set>)
+#  if __has_include(<generator>)
+#    error "please update the header information for <generator> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<generator>)
+#  if __has_include(<hazard_pointer>)
+#    error "please update the header information for <hazard_pointer> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<hazard_pointer>)
+#  if __has_include(<linalg>)
+#    error "please update the header information for <linalg> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<linalg>)
+#  if __has_include(<rcu>)
+#    error "please update the header information for <rcu> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<rcu>)
+#  if __has_include(<spanstream>)
+#    error "please update the header information for <spanstream> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<spanstream>)
+#  if __has_include(<stacktrace>)
+#    error "please update the header information for <stacktrace> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<stacktrace>)
+#  if __has_include(<stdfloat>)
+#    error "please update the header information for <stdfloat> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<stdfloat>)
+#  if __has_include(<text_encoding>)
+#    error "please update the header information for <text_encoding> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<text_encoding>)
+#endif // _WIN32
 
 export module std;
 
diff --git a/libcxx/utils/generate_libcxx_cppm_in.py b/libcxx/utils/generate_libcxx_cppm_in.py
index 2d3f829847fb9..0390ce5067f40 100644
--- a/libcxx/utils/generate_libcxx_cppm_in.py
+++ b/libcxx/utils/generate_libcxx_cppm_in.py
@@ -57,18 +57,31 @@ def write_file(module):
             else:
                 module_cpp_in.write(f"#include <{header}>\n")
 
-        module_cpp_in.write("\n// *** Headers not yet available ***\n")
+        module_cpp_in.write(
+            """
+// *** Headers not yet available ***
+//
+// This validation is mainly to catch when a new header is added but adding the 
+// corresponding .inc file is forgotten. However, the check based on __has_include
+// alone doesn't work on Windows because the Windows SDK is on the include path,
+// and that means the MSVC STL headers can be found as well, tricking __has_include
+// into thinking that libc++ provides the header.
+//
+#ifndef _WIN32
+"""
+        )
         for header in sorted(headers_not_available):
             module_cpp_in.write(
                 f"""\
-#if __has_include(<{header}>)
-#  error "please update the header information for <{header}> in headers_not_available in utils/libcxx/header_information.py"
-#endif // __has_include(<{header}>)
+#  if __has_include(<{header}>)
+#    error "please update the header information for <{header}> in headers_not_available in utils/libcxx/header_information.py"
+#  endif // __has_include(<{header}>)
 """
             )
 
         module_cpp_in.write(
-            f"""
+            f"""#endif // _WIN32
+
 export module {module};
 {'export import std;' if module == 'std.compat' else ''}