diff --git a/racket/src/Makefile.in b/racket/src/Makefile.in
index e15d1367b9..7870fa0e60 100644
--- a/racket/src/Makefile.in
+++ b/racket/src/Makefile.in
@@ -255,7 +255,7 @@ clean:
 SRC_MAKEFILES = $(srcdir)/Makefile.in $(srcdir)/racket/Makefile.in \
                 $(srcdir)/racket/src/Makefile.in $(srcdir)/gracket/Makefile.in \
                 $(srcdir)/racket/gc2/Makefile.in $(srcdir)/gracket/gc2/Makefile.in \
-                $(srcdir)/racket/dynsrc/Makefile.in
+                $(srcdir)/rktio/Makefile.in $(srcdir)/racket/dynsrc/Makefile.in
 
 reconfigure:
 	$(MAKE) Makefile
diff --git a/racket/src/foreign/foreign.c b/racket/src/foreign/foreign.c
index ad7a61e060..56abd8587d 100644
--- a/racket/src/foreign/foreign.c
+++ b/racket/src/foreign/foreign.c
@@ -263,8 +263,11 @@ static Scheme_Object *foreign_ffi_lib(int argc, Scheme_Object *argv[])
       /* openning the executable is marked by a NULL handle */
       handle = NULL;
       null_ok = 1;
-    } else
-      handle = LoadLibraryW(WIDE_PATH(name));
+    } else {
+      wchar_t *wp;
+      wp = scheme_path_to_wide_path(MYNAME, name);
+      handle = LoadLibraryW(wp);
+    }
 #   else /* WINDOWS_DYNAMIC_LOAD undefined */
 #   ifdef __ANDROID__
     if (!name) handle = RTLD_DEFAULT; else
diff --git a/racket/src/foreign/foreign.rktc b/racket/src/foreign/foreign.rktc
index cab6fea4df..6f3771bade 100755
--- a/racket/src/foreign/foreign.rktc
+++ b/racket/src/foreign/foreign.rktc
@@ -233,8 +233,11 @@ THREAD_LOCAL_DECL(static Scheme_Hash_Table *opened_libs);
         /* openning the executable is marked by a NULL handle */
         handle = NULL;
         null_ok = 1;
-      } else
-        handle = LoadLibraryW(WIDE_PATH(name));
+      } else {
+        wchar_t *wp;
+        wp = scheme_path_to_wide_path(MYNAME, name);
+        handle = LoadLibraryW(wp);
+      }
     }{
       @@IFDEF{__ANDROID__}{if (!name) handle = RTLD_DEFAULT; else}
       @@IFDEF{__CYGWIN32__}{if (!name) { handle = RTLD_DEFAULT; null_ok = 1; } else}
diff --git a/racket/src/racket/src/dynext.c b/racket/src/racket/src/dynext.c
index ab8076aa14..83fe54f7e8 100644
--- a/racket/src/racket/src/dynext.c
+++ b/racket/src/racket/src/dynext.c
@@ -299,16 +299,18 @@ static Scheme_Object *do_load_extension(const char *filename,
     HINSTANCE dl;
     Setup_Procedure f;
     char *vers;
-  
-    dl = LoadLibraryW(WIDE_PATH(filename));
+    wchar_t *wp;
+
+    wp = scheme_path_to_wide_path(NULL, filename);
+    dl = LoadLibraryW(wp);
     if (!dl) {
       long err;
       err = GetLastError();
       scheme_raise_exn(MZEXN_FAIL_FILESYSTEM,
-		       "load-extension: could not load file\n"
+                       "load-extension: could not load file\n"
                        "  path: %q\n"
                        "  system error: %E",
-		       filename, err);
+                       filename, err);
     }
     
     handle = (void *)dl;
diff --git a/racket/src/racket/src/file.c b/racket/src/racket/src/file.c
index e695e90e73..261c32d46e 100644
--- a/racket/src/racket/src/file.c
+++ b/racket/src/racket/src/file.c
@@ -1049,62 +1049,38 @@ int scheme_os_setcwd(char *expanded, int noexn)
 }
 
 #ifdef DOS_FILE_SYSTEM
-#define WC_BUFFER_SIZE 1024
-THREAD_LOCAL_DECL(static void *file_path_wc_buffer);
 
-static int wc_strlen(const wchar_t *ws)
+static intptr_t wc_strlen(const wchar_t *ws)
 {
-  int l;
+  intptr_t l;
   for (l =0; ws[l]; l++) { }
   return l;
 }
 
-wchar_t *scheme_convert_to_wchar(const char *s, int do_copy)
-     /* This function uses '\t' in place of invalid UTF-8 encoding
-	bytes, because '\t' is not a legal filename under Windows. */
+wchar_t *scheme_path_to_wide_path(const char *who, const char *p)
 {
-  intptr_t len, l;
-  wchar_t *ws;
+  wchar_t *wp, *gc_wp;
+  intptr_t len;
+  
+  wp = rktio_path_to_wide_path(scheme_rktio, p);
+  if (wp) {
+    len = wc_strlen(wp);
+    gc_wp = scheme_malloc_atomic((len + 1) * sizeof(wchar_t));
+    memcpy(gc_wp, wp, (len + 1) * sizeof(wchar_t));
+    free(wp);
+    return gc_wp;
+  }
+  if (who)
+    scheme_raise_exn(MZEXN_FAIL_FILESYSTEM,
+                     "%s: could not read file\n"
+                     "  path: %q\n"
+                     "  system error: %R",
+                     p);
 
-  l = strlen(s);
-  len = scheme_utf8_decode(s, 0, l,
-			   NULL, 0, -1,
-			   NULL, 1/*UTF-16*/, '\t');
-
-  if (!do_copy && (len < (WC_BUFFER_SIZE-1))) {
-    if (!file_path_wc_buffer) {
-      REGISTER_SO(file_path_wc_buffer);
-      file_path_wc_buffer = scheme_malloc_atomic(sizeof(wchar_t) * WC_BUFFER_SIZE);
-    }
-    ws = (wchar_t *)file_path_wc_buffer;
-  } else
-    ws = (wchar_t *)scheme_malloc_atomic(sizeof(wchar_t) * (len + 1));
-  scheme_utf8_decode(s, 0, l,
-		     (unsigned int *)ws, 0, -1,
-		     NULL, 1/*UTF-16*/, '\t');
-  ws[len] = 0;
-  return ws;
-}
-
-char *scheme_convert_from_wchar(const wchar_t *ws)
-{
-  intptr_t len, l;
-  char *s;
-
-  l = wc_strlen(ws);
-  len = scheme_utf8_encode((unsigned int *)ws, 0, l,
-			   NULL, 0,
-			   1/*UTF-16*/);
-  s = (char *)scheme_malloc_atomic(len + 1);
-  scheme_utf8_encode((unsigned int *)ws, 0, l,
-		     s, 0,
-		     1/*UTF-16*/);
-  s[len] = 0;
-  return s;
+  return NULL;
 }
 #endif
 
-
 Scheme_Object *scheme_get_file_directory(const char *filename)
 {
   int isdir;
diff --git a/racket/src/racket/src/schpriv.h b/racket/src/racket/src/schpriv.h
index 0eee605d70..671bd30a48 100644
--- a/racket/src/racket/src/schpriv.h
+++ b/racket/src/racket/src/schpriv.h
@@ -4241,25 +4241,7 @@ Scheme_Object *scheme_extract_relative_to(Scheme_Object *obj, Scheme_Object *dir
 Scheme_Object *scheme_find_links_path(int argc, Scheme_Object *argv[]);
 
 #ifdef DOS_FILE_SYSTEM
-# define WIDE_PATH(s) scheme_convert_to_wchar(s, 0)
-# define WIDE_PATH_COPY(s) scheme_convert_to_wchar(s, 1)
-# define NARROW_PATH(s) scheme_convert_from_wchar(s)
-extern wchar_t *scheme_convert_to_wchar(const char *s, int do_copy);
-extern char *scheme_convert_from_wchar(const wchar_t *ws);
-#else
-# define WIDE_PATH(s) s
-# define WIDE_PATH_COPY(s) s
-# define NARROW_PATH(s) s
-#endif
-
-#if defined(DOS_FILE_SYSTEM) && !defined(__CYGWIN32__)
-# define MSC_W_IZE(n) _w ## n
-# define MSC_WIDE_PATH(s) WIDE_PATH(s)
-# define MSC_WIDE_PATH_COPY(s) WIDE_PATH_COPY(s)
-#else
-# define MSC_W_IZE(n) MSC_IZE(n)
-# define MSC_WIDE_PATH(s) s
-# define MSC_WIDE_PATH_COPY(s) s
+wchar_t *scheme_path_to_wide_path(const char *who, const char *p);
 #endif
 
 /*========================================================================*/
diff --git a/racket/src/rktio/rktio.h b/racket/src/rktio/rktio.h
index f9626a0065..56fca913ce 100644
--- a/racket/src/rktio/rktio.h
+++ b/racket/src/rktio/rktio.h
@@ -872,9 +872,19 @@ rktio_ok_t rktio_shell_execute(rktio_t *rktio,
 			       const char *arg,
 			       const char *dir,
 			       int show_mode);
-/* Support only on Windows to run `ShellExecute`. The `dir` argument
+/* Supported only on Windows to run `ShellExecute`. The `dir` argument
    needs to have normalized path separators. */
 
+/*************************************************/
+/* Path conversion                               */
+
+void *rktio_path_to_wide_path(rktio_t *rktio, const char *p);
+char *rktio_wide_path_to_path(rktio_t *rktio, const void *wp);
+/* Convert to/from the OS's native path representation. These
+   functions are useful only on Windows, where each `void *`
+   is actually a `wchar_t*`. The `rktio_path_to_wide_path`
+   function can fail and report `RKTIO_ERROR_INVALID_PATH`. */
+
 /*************************************************/
 /* Errors                                        */
 
diff --git a/racket/src/rktio/rktio_wide.c b/racket/src/rktio/rktio_wide.c
index 9be43f6b01..fb72092d55 100644
--- a/racket/src/rktio/rktio_wide.c
+++ b/racket/src/rktio/rktio_wide.c
@@ -5,6 +5,17 @@
 
 #ifdef RKTIO_SYSTEM_UNIX
 void rktio_init_wide(rktio_t *rktio) { }
+
+void *rktio_path_to_wide_path(rktio_t *rktio, const char *p)
+{
+  return strdup(p);
+}
+
+char *rktio_wide_path_to_path(rktio_t *rktio, const void *wp)
+{
+  return strdup((char *)wp);
+}
+
 #endif
 
 #ifdef RKTIO_SYSTEM_WINDOWS
@@ -308,4 +319,14 @@ char *rktio_convert_from_wchar(const wchar_t *ws, int free_given)
   return s;
 }
 
+void *rktio_path_to_wide_path(rktio_t *rktio, const char *p)
+{
+  return WIDE_PATH_copy(p);
+}
+
+char *rktio_wide_path_to_path(rktio_t *rktio, const void *wp)
+{
+  return NARROW_PATH_copy(wp);
+}
+
 #endif