diff --git a/win32/ioutil.c b/win32/ioutil.c
index 7eeddfbb70d..4f3e2d0bd67 100644
--- a/win32/ioutil.c
+++ b/win32/ioutil.c
@@ -538,6 +538,7 @@ PW32IO size_t php_win32_ioutil_dirname(char *path, size_t len)
 	return ret_len;
 }/*}}}*/
 
+/* Partial normalization can still be acceptable, explicit fail has to be caught. */
 PW32IO php_win32_ioutil_normalization_result php_win32_ioutil_normalize_path_w(wchar_t **buf, size_t len, size_t *new_len)
 {/*{{{*/
 	wchar_t *pos, *idx = *buf, canonicalw[MAXPATHLEN];
@@ -545,6 +546,7 @@ PW32IO php_win32_ioutil_normalization_result php_win32_ioutil_normalize_path_w(w
 
 	if (len >= MAXPATHLEN) {
 		SET_ERRNO_FROM_WIN32_CODE(ERROR_BAD_LENGTH);
+		*new_len = 0;
 		return PHP_WIN32_IOUTIL_NORM_FAIL;
 	}
 
@@ -554,6 +556,8 @@ PW32IO php_win32_ioutil_normalization_result php_win32_ioutil_normalize_path_w(w
 	}
 
 	if (S_OK != canonicalize_path_w(canonicalw, MAXPATHLEN, *buf, PATHCCH_ALLOW_LONG_PATHS)) {
+		/* Length unchanged. */
+		*new_len = len;
 		return PHP_WIN32_IOUTIL_NORM_PARTIAL;
 	}
 	ret_len = wcslen(canonicalw);
@@ -562,6 +566,8 @@ PW32IO php_win32_ioutil_normalization_result php_win32_ioutil_normalize_path_w(w
 			wchar_t *tmp = realloc(*buf, (ret_len + 1) * sizeof(wchar_t));
 			if (!tmp) {
 				SET_ERRNO_FROM_WIN32_CODE(ERROR_NOT_ENOUGH_MEMORY);
+				/* Length unchanged. */
+				*new_len = len;
 				return PHP_WIN32_IOUTIL_NORM_PARTIAL;
 			}
 			*buf = tmp;
diff --git a/win32/ioutil.h b/win32/ioutil.h
index 120d69213dd..a22ca3eb143 100644
--- a/win32/ioutil.h
+++ b/win32/ioutil.h
@@ -177,17 +177,17 @@ __forceinline static wchar_t *php_win32_ioutil_conv_any_to_w(const char* in, siz
 			return NULL;
 		}
 
-		/* The return can be ignored here, as the normalization can fail for
-		   various reasons not directly related to the operation itself.
-		   Partial normalization could still do a better job further. And
-		   otherwise, the path might be unchanged which is ok if the path
-		   was valid long one. */
-		(void)php_win32_ioutil_normalize_path_w(&mb, mb_len, &new_mb_len);
+		if (PHP_WIN32_IOUTIL_NORM_FAIL == php_win32_ioutil_normalize_path_w(&mb, mb_len, &new_mb_len)) {
+				free(ret);
+				free(mb);
+				return NULL;
+		}
 
 		if (new_mb_len > mb_len) {
 			wchar_t *tmp = (wchar_t *) realloc(ret, (new_mb_len + 1) * sizeof(wchar_t));
 			if (!tmp) {
 				free(ret);
+				free(mb);
 				return NULL;
 			}
 			ret = tmp;