diff --git a/nasmlib/file.c b/nasmlib/file.c
index c9cf8e36e..15fde9adf 100644
--- a/nasmlib/file.c
+++ b/nasmlib/file.c
@@ -45,7 +45,24 @@
  */
 #ifdef _WIN32
 #include <wchar.h>
-#include <stringapiset.h>
+/*
+ * <windows.h> is needed for MultiByteToWideChar()/CompareStringOrdinal()
+ * (normally declared via <stringapiset.h>).  Windows SDK headers like
+ * <stringapiset.h> are only guaranteed to work when pulled in through the
+ * normal <windows.h> pipeline, which sets up SDK-internal architecture
+ * macros (_X86_, _AMD64_, ...) derived from the compiler's own
+ * _M_IX86/_M_X64/etc; including such a leaf header directly can fail with
+ * a "No Target Architecture" #error from <winnt.h>.
+ *
+ * <windows.h> is deliberately *not* included from compiler.h: it #defines
+ * NEAR and FAR (as legacy no-op calling-convention keywords), which clash
+ * with NASM's own NEAR/FAR opflags bits from opflags.h.  Keep the
+ * inclusion local to the few files, like this one, that actually need
+ * Windows API declarations, and define WIN32_LEAN_AND_MEAN to keep the
+ * exposed surface (winsock, GDI, shell, DDE, RPC, crypto, ...) minimal.
+ */
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
 
 typedef wchar_t *os_filename;
 typedef wchar_t  os_fopenflag;