diff --git a/win32/ioutil.h b/win32/ioutil.h
index 9e0c1ce15ca..8298912a0e0 100644
--- a/win32/ioutil.h
+++ b/win32/ioutil.h
@@ -137,7 +137,7 @@ typedef enum {
 #define PHP_WIN32_IOUTIL_CHECK_PATH_W(pathw, ret, dealloc) do { \
 		if (!PHP_WIN32_IOUTIL_PATH_IS_OK_W(pathw, wcslen(pathw))) { \
 			if (dealloc) { \
-				free(pathw); \
+				free((void *)pathw); \
 			} \
 			SET_ERRNO_FROM_WIN32_CODE(ERROR_ACCESS_DENIED); \
 			return ret; \