diff --git a/lib/curl_setup.h b/lib/curl_setup.h
index db438a8b0a..886a881493 100644
--- a/lib/curl_setup.h
+++ b/lib/curl_setup.h
@@ -95,9 +95,9 @@
                                       unlink(), etc. */
 #endif
 #ifndef _CRT_SECURE_NO_WARNINGS
-#define _CRT_SECURE_NO_WARNINGS  /* for __sys_errlist, __sys_nerr, _open(),
-                                    _wfopen(), _wopen(), fopen(), freopen(),
-                                    getenv(), gmtime(), sprintf(), strcpy(),
+#define _CRT_SECURE_NO_WARNINGS  /* for _open(), _wfopen(), _wopen(), fopen(),
+                                    freopen(), getenv(), gmtime(), sprintf(),
+                                    strcpy(),
                                     in tests: localtime(), open(), sscanf() */
 #endif
 #endif /* _MSC_VER */
diff --git a/lib/curlx/strerr.c b/lib/curlx/strerr.c
index 047588ed18..376f68b0b2 100644
--- a/lib/curlx/strerr.c
+++ b/lib/curlx/strerr.c
@@ -287,17 +287,12 @@ const char *curlx_strerror(int err, char *buf, size_t buflen)
   *buf = '\0';
 
 #ifdef _WIN32
-  /* 'sys_nerr' is the maximum errno number, it is not widely portable */
-  if(err >= 0 && err < sys_nerr)
-    SNPRINTF(buf, buflen, "%s", sys_errlist[err]);
-  else {
-    if(
+  if((!strerror_s(buf, buflen, err) || !strcmp(buf, "Unknown error")) &&
 #ifdef USE_WINSOCK
-      !get_winsock_error(err, buf, buflen) &&
+     !get_winsock_error(err, buf, buflen) &&
 #endif
-      !curlx_get_winapi_error((DWORD)err, buf, buflen))
-      SNPRINTF(buf, buflen, "Unknown error %d (%#x)", err, err);
-  }
+     !curlx_get_winapi_error((DWORD)err, buf, buflen))
+    SNPRINTF(buf, buflen, "Unknown error %d (%#x)", err, err);
 #else /* !_WIN32 */
 
 #if defined(HAVE_STRERROR_R) && defined(HAVE_POSIX_STRERROR_R)